Are the bugs as bad as I read in Chiang Mai? Any suggestions of a good spray or wipe to help?

I have no idea what you've read. I have certainly encountered mosquitos in CM, but there were not swarms of them. Of course, in any case, it is wise to use repellant, as dengue is endemic in Thailand (and many other tropical and semi-tropical places in the world, including Hawaii).

There are two effective repellants: deet and picardin. Just make sure that whatever you buy contains one of these.

I've never been bothered by mosquitos in Chiang Mai. They don't like AC so be sure your room is equipped for nighttime. If I recall, the recommendation is any repellent with over 50% deet, cover up in the evening, use repellent daytime too (different mosquito). You probably won't even notice them.

some people react strongly to mozzie bites whilst others don't - this is not necessarily representative of how much your are actually being bitten.
Mosquitoes exist throughout Thailand and their numbers rise and fall....at present where I live in Chonburi they seem to have risen to almost plague proportions. however they don't appear to be the Aedes/Dengue carrying type.
the best advice is to not get bitten regardless - so follow standard advice about DEET and clothing.
Repellants containing more than 33% DEET have been shown to have no added efficacy.
Both Picaridin and DEET are known to be effective - the side effects are in most cases exaggerated by some of the media.

Some "alternative" plant-based repellents work but for a much shorter period....and are more likely to be washed/sweated off.

No repellent is 100%

Long sleeved shirts and long pants are also very good protection......mozzies are attracted by large areas of skin and silhouettes - so wear light colors.

See what repellents are sold in a local supermarket, it might be more effective than Jungle Formula etc.

Avon so-soft is good. It's not a repellent, but the spray provides a barrier on the skin. Use it in addition to a repellent.

If you're eating al fresco, burn a mosquito coil under your table. Make sure the fumes aren't blowing into your face.

Don't burn a coil in your hotel room!

Bright colours attract mozzies.

If you're running the a/c don't open the windows.

Use a plug-in repellent in your hotel room.

Don't leave any windows ajar during the day.

Mozzies will get into your room any way they can. So in the bathroom keep the sink, bath/shower plug in the hole. A lot of rooms don't have plugs in the bathroom, so take a couple of universal sink plugs.

As has been said give mozzies the minimum target, and cover up especially at dawn and dusk.

Avon Skin so Soft has a small amount of citronella, but trials have shown it is no better than no repellant at all.

Kathie, it's not advertised as a repellent, yet lots of folk recommend Avon so-soft as a barrier.

I was sceptical, tried it, and so long as it was used alongside a deet based repellent it did the job.

I use a nice thick layer of goose grease along with my deet repellent and that works very well, too. But bring your own as it's difficult to come by in parts of Asia. Duck doesn't work as well, IME.

Foie gras in a tub!

Liver? I think not.

Be careful when mixing other items with repellents as they can nullify the repellents.

for example suncream and repellant don't work together..i believe the repellent nullifies the screen.

Coils etc have a lot of bad publicity as they don't come under normal medical regulations etc.
However if you have a mozzie problem in your room leave a coil going while you are out and extinguish or remove it when you get back, that way you will at least have reduced the population on your return.
i wouldn't sleep with a coil in the room.
they are good on balconies too.

"Bright colours attract mozzies.

If you're running the a/c don't open the windows.

Use a plug-in repellent in your hotel room.

Don't leave any windows ajar during the day.

Mozzies will get into your room any way they can. So in the bathroom keep the sink, bath/shower plug in the hole. A lot of rooms don't have plugs in the bathroom, so take a couple of universal sink plugs."

some of these ideas are new to me!
some are just plain common sense.

as far as I'm aware mosquitoes are color blind.
why would anyone leave a window open when the air is on? you're just cooling down the outside - a pointless and unachievable task.
Mozzies are good at getting into your room but they can't swim round an "s" bend and unless you have a hatchery in there or the toilet owl it seems unlikely they ca get it that way.
Plug-in repellents and coils use the same chemicals - so either way, you are releasing these into your room...and there is some compelling stuff to suggest they aren't good for us....although I haven't read any serious papers on that yet.

If you do have the widows open during the day, or people coming in and out of the room, it is possible that mozzies will get in so be prepared to spay the room early evening or use a coil or electronic device to clear the room before you go to bed.
if you have a really bad mozzie problem you can probably find a mosquito net at most supermarkets.

<<<However if you have a mozzie problem in your room leave a coil going while you are out and extinguish or remove it when you get back, that way you will at least have reduced the population on your return.>>>

Chances are you'll return to a choking blue mist!

<<<some of these ideas are new to me! some are just plain common sense.>>>

Nowt wrong with new ideas, especially if the work. I pick ideas up from other people all the time, try them, and if they work for me, then I like to share the information.

Some are absolute plain common sense. But a lot of people leave their common sense back on the aeroplane. There's plenty of evidence of that on any travel forum you might visit, even this one! Gentle reminders, especially if they are on-topic are usually welcomed.

I think you may have picked up a few "wrong'uns" on the way? - "blue mist"???

Yep. A mozzie coil burn for up to 8 hours. If you leave one burning away in your hotel room for a few hours then you'll return to a foggy room. That was my experience on the one time I tried it in Vientiane.

http://en.wikipedia.org/wiki/Mosquito_coil

Sounds like you were unlucky - after nearly 20 years in the tropics and burning of many different kinds of coils and sticks both in and outdoors, i've never had a problem with "mist" or "fog". There is often a smell left behind but that's about it.
One thing I would recommend though is using a "cage" for those coils - they are made out of recycled metal and can be bought for just a few baht in any supermarket next to where they sell the coils. They make the coil easy to handle, protect it from kicks etc and make them safer.

When it comes to clearing mozzies outdoors, my favourites are still some of the large sticks and giant coils for outdoor use sold in Oz....try to keep a few in stock for caping, BBQ's and clearing mozzies away from balconies etc.