We did a ten day trip in Spain that was a bit rush but worked well. Into Madrid - 3 days, Cordoba - 1, Seville -3, Granada - 3, and home from Malaga. With short time an open jaw ticket works very well.

First I suggest that you buy a good guidebook, such as Fodors, Michelen Green Guide, Lonely Planet. What are your interests? What made you decide on Spain and/or Italy? How long to spend in each country depends on your interests, and your travel style; slow & easy to savor the ambience, or fast so you can see more places & perhaps return some day to the country that you like the best & spend more time at a future date.

One suggestion would be to visit 2 or 3 major cities if you go to both countries, such as Rome, Barcelona & Madrid. Or do you prefer to mix it up with one major city and the countryside and/or smaller cities in only one country. For example, you could visit only Italy, and go to Rome, Venice & Florence, which is popular with first timers to Italy. Or eliminate Venice & go to Tuscany. If you only visit Spain, you could visit Barcelona and Madrid with day trips to Toledo and/or Segovia. When I traveled to Spain, I went to Barcelona for 5 days, and then we rented a car for 3 nights/4 days for a roadtrip through Costa Brava & the Pyrenees. So we saw a major city, the coast & the mountains.

If you want to see a little bit of each country, you could fly to Rome, then fly to Barcelona, then take the high speed train to Madrid. Or fly from Rome to Madrid, then take the high speed train to Barcelona. If you visit both countries, you would buy an open-jaw ticket.

I recommend at least 5 days in Rome and 5 days in Barcelona. It's been a long time since I've been to Florence (for only a day), and it wasn't enough. haven't been to Madrid yet but most people seem to recommend 3 - 4 nights in Madrid including day trips.

But as I said earlier, you must buy some guide books first to see what each country & city has to offer and decide what interests you the most.

Is it Feb or Apr?
Is it 10 days on the ground--more, less??

Spain takes 6 weeks. Italy takes more than Spain.

Come back when you have a clue.

If you have a choice, travel in April, not February.

With 10 days, visit either Spain or Italy. Even with 10 days you can see only a little of whichever country you visit.

Get a good guidebook and decide which you prefer. Then come back and we'll help you with the details.

I agree with mamcalice.
Italy and Spain are both big countries and there's so much to see just in one country, just visit one in the 10 days you have.

Feb is winter everywhere in europe - Apr had a much better chance of decent weather and longer days.

Suggest you get some guide books and decide what YOU want to see and do - which is likely to be very different from what I - or anyone else answering - wants to see/do.

I have traveled to Spain in Feb.While it is cold, we had a wonderful time and less tourists.

I would also say Spain would a good choice at least to see some of it. Start in Madrid - fan out south.There is absolutely plenty to keep you busy from Toledo to Ahlhambra to Seville to Marbella. Barcelona needs several days to do it justice,

A couple of days in each would keep you busy for 10 days.

But, what are your interests?

On several trips over the years I've spent between a week and 6 months at a time in Europe. I really didn't enjoy the week that much even though it was in Paris... just as I seemed to get into the flow it was time to go. For a first trip I'd recommend 2 weeks.

Of course any time you can add is good, 10 days is what I consider a minimum, ( my shortest trip ever was 9 days in Paris and it was too short!) but I do understand most Americans don't get much vacation time( horrible!)
SO with 10 days my thoughts would be one country, two, maybe max three cities if you like a more rushy type holiday( some people do).
I too would push for April, abit later then earlier, as I prefer better then worse weather, but there are never any gurantees with weather no matter when you go.

I have only been to Spain once, and only for a week ,so won't spout on about it, but I did enjoy it very much, next time longer visit.
Italy can keep you busy for months if you let it, but if you just narrow it down to say Rome, Venice and Florence you will have had a nice taste..

I know lots of people who spend 5 days in Spain and 5 days in Italy in winter and have a blast. For February, I would pick Barcelona or Sevilla, and either Rome or Napoli/Pompei. Depends on your interests and what you like to eat and drink.

April is also great -- although I would definitely want to avoid Easter. In April, you have less risk of snow disrupting your travel plans and can generally spend more time outdoors comfortably.

Many people obviously prefer to visit just one country. It is all a matter of personal taste.

There is everything to do in either country, and both of them have sufficiently mild weather that apart from obvious summer activities like swimming, you can do just about anything from go to soccer matches to attend cooking classes to touring ancient ruins to touring motorcycle factories -- and on and on. Only you know why you might like to visit either place.

Spain can keep you busy for years. It is a very varied place. Italy too. Some people like Rome or Naples. Some hate it. Some like Barcelona. (I don't.) Dig into some guidebooks and think about what you enjoy and, again, what made you choose these places rather than Germany and France, or Ireland and Turkey. Just make sure Italy and Spain have you want.

Ignore bob the navigator..We are here to help if we can. Spain is special..Had no languge problems but got a lot of hand gesture exercise with a smattering of Spanish. there is alomost someone efverywhere who speaks English in Europe (including a dishwasher in a very remote village Portugal..Go figure). Cold is cold no matter where you end up...Spring break 2012 if snowed in Salamanca, Avila, Penninsular battle ground and Madrid.. Layers are the way to go. Easter(Semana Sancta is a real experience albeit crowded but none the less enjoyable..Where ever you decide to go. "Just do it"!!! you'll love the ambiance, hospitality, people, food , etc, etc,etc. Haven't been to Italy except for 5 days in 2010 along the Med. coast , inland to Florence and Cinque Terre. beautiful scenery when you could see it due to mega amounts of tunnels and I would personally choose Spain but to each his/her own!!!

But Bob is right--maybe many of us do not mind taking a shot in the dark, but it is expecting a bit much to not give more specifics when asking a favor. I don't think he meant to be rude--just to let the OP know that s/he needs to provide a bit and do some independent research as well. Asking "things to do" is not good question etiquette either.

Agree - asking us to be your tout guide is not the way it is done.

Realize newbies may not know much.

But it is really helpful if people have SOME information/ opinions when they come here.

(I learned my lesson several years ago giving a lot of info on upscale NY restaurants to a poster who later said they wanted only steak or lobster. Getting some info upfront can avoid a lot of wasted time.)