Close to fabulous Blackpool is the fabled Lake District - easily reached by train in a few hours (Windermere is the rail head and a nice town to base in - take open-air doubledecker buses around to all the hotspots of the Lake District - in Ireland I would try to get to the West Coast - to me the most interesting and gorgeous part of the country - and where even today the local tongue is Gaellic and not English, though everyone speaks English as well - the Dingle Peninsula or the Connemara are two great places on the West Coat that can be reached by train and or bus.

Bath would also be a nice stop not far from Blackpool - to me along with York Bath is the finest looking and most interesting city in England. Easy by train - and only 90 minutes by train from London.

Bath is lovely, but nowhere near Blackpool...

We enjoyed Liverpool:

http://www.fodors.com/community/europe/a-daytrip-to-liverpool.cfm

and as mentioned, the Lake District:

http://www.fodors.com/community/europe/weekend-in-the-lake-district.cfm

North Wales is very nice as well, but a little tougher without a car.

I did North Wales without a car and it was a snap - trains and buses go everywhere and you can get a day pass at an incredibly cheap price - Llandudno makes a great base for those looking for inexpensive accommodation and a lively town - an old seaside resort - day trip from there easily to nearby Conwy - an ancient walled town or to Mt Snowdon (thrilling steam train goes up there) or to Caernaveron (sp?) famous castle and town where the Duke of Wales is officially crowned (or whatever they do - investititure? or to lovely Beaumarais castle - the castle of your dreams plunked right on the sea or to hop the famous Ffestionog (sp?) Railway.

North Wales yes close to Blackpool and sans car no problem IME.

and yes Bath is farther than I though by rail - nearly 5 hours - I was thinking if someone were going back to London that could be a stop but OP says not planning on going to London.

You mention music, you might want to divide your time in Ireland between Dublin and Galway, which has a great traditional music scene. Train is around 3 hours, perhaps less.

The bus service in North Wales is very good but your time is a bit limited for a lot of exploration.

You will find lots to do and see in Dublin. Some travelers to Ireland tend to short change it. I won't bother with a list, but also how about booking day trips north to Boyne Valley seeing ancient Newgrange and south to Glendalough. We did lots of walking in the city so no car either. Just reading a book by columnist Roger Rosenblatt who is remembering years ago enjoy many plays at the Globe and Abbey Theatres as did we.
If time, of course, you can schedule a day trip elsewhere.

Which festival? If it's the Rebellion Fest, then I'm hoping you have your lodging set for Edinburgh (yes, Edinburgh) b/c you'll be there at the most crowded time of year. Edinburgh triples in size in August due to its various festivals.

<<I have been to London previously and would go back in a heartbeat, but I am unsure about distance, etc or if there are other sights closer and more convenient to Blackpool worth seeing.>>

Take him to London. There is no substitute. Train from Blackpool to London is less than 3 hours with a change (probably in Liverpool) - which is not long at all.

As for Dublin, what do you like to do? Five days (five nights?) there seems like a lot, whereas in London it'd be a good start.

Wow...everyone is awealth of information! Thank you!!

BigRuss - We are attending the Rebellion Festival in Blackpool and we have lodging set right by Wintergarden. So...London is doable, huh? I am hoping maybe my other half will be tired of the festival after day 3 truthfully so we could have 3 extra days instead of 2. So much to consider.

As for Dublin - we have lodging for the 5 days, but are not necessarily married to the idea of having to stay in Dublin itself for all 5. We fly in from Glasgow the evening of 8/2 then out the eve of 8/7 to Manchester. I would like to see as many of Ireland's highlights as possible...and if that means renting a car, we will, but we hadn't planned on it.

Cathinjoetown, Ozarksbill and BigRuss...

One other question specific to Ireland. We will be celebrating my boyfriend's bday while there so is there anything really special or completely exciting to save for that day? More so than everything else that I am sure is amazing, given that I am Irish and really looking forward to this.