If you're going to do some travelling in Ireland, the best thing to do is get your hands on one of Georgina Campbell's Irish foodie guidebooks (review of her latest one here: http://www.bibliocook.com/archives/2006/01/georgina_campbe.html) as she a good mixture of city-based high class restaurants alongside reasonable B&Bs and the kind of local deli or coffee shop that you'll encounter if you're travelling around.
My recommendation for the Aran Islands is the never-beaten Mainistir House (http://www.mainistirhousearan.com) on Inis Mór. It's supposed to be a hostel but it's more like a luxury B&B, albeit without en suite bathrooms, but with the nicest food that you're going to find on the islands. Homemade brown soda bread and porridge for breakfast and they do a gorgeous "vaguely vegetarian" dinner (can be prebooked even if you're not staying there) for €15. Well worth trying out.
I strongly recommend the restaurant at the Ballinalacken Hotel in Doolin and the Doolin Cafe. Both places serve imaginative and fresh local food that defy stereotypes of Irish cooking. I have had great seafood at the Ballinalacken Hotel on several occasions and not been disappointed. Service is fairly polished and there is a decent wine list. The view of the Cliffs of Moher doesn't hurt, either. The Doolin Cafe is a little more laid back but also shows high standards (we learned of this place from Marian, who runs the show at the Ballinalacken). They also serve Biddy Beer, an up and coming Irish microbrew featured in the NY Times a few days ago. Beer notwithstanding, this is a serious place. I also had a good lunch over in Galway at Kirby's, a modern place just off of Quay Street. One disappointment was Moran's Oyster Cottage on the road to Galway from Doolin. The food was OK but very overpriced, IMHO.
Hope that this helps.
I guess I'll have to disclose the fact that the place I'm going to recommend is managed by my wife's cousin and her husband. It's called Fanny O'Dea's pub and it's in Lissycasey, which is about a ten minute drive west of Ennis.
Ennis itself is a neat town and seems to have lots of cool pubs and restaurants.
Although I'm slightly biased, I can only rave about Fanny O'Dea's. It's been opened since the late 1600's, and owned by the same family since. My wife's cousin started running the place about two years ago, and I think they started serving food then. The menu is traditional Irish pub food, but the chef does a great job with everything. The bacon and cabbage was fantastic, and everything else looked great. Everything is priced very reasonably. If I remember correctly, only about 10 or 12 euro per entree.
And, again...I am biased, but in my 12 years of travelling to Ireland, I had the best pint of Guinness there. They take serious care that all lines are meticulously cleaned. They even moved the Guinness closer to the taps than the other kegs so that the run is not too long, and the temperature does not go up above 4 degrees celcius by the time it hits the glass, etc., etc., etc...
The pub is also very charming--thatched roof, continuously running turf fire, etc. And it is honestly not too touristy. Mostly locals and people stopping on the road for a bite to eat.