If you want something affordable, homey but with lots of taste, then try KC Peaches.
My husband and I ended up eating there most evenings when we were in Dublin for a week in Jan. 2007. The hot entree (one meat, one veg usually) changes every night, and they have wonderfully prepared vegetables--a rarity in Ireland that we really appreciated.
The place is a mixture of gourmet food shop, coffee bar, sanwiches, bakery, and up-market prepared food take-away (think like a Whole Foods counter, but smaller in scale and quieter, at least during the dinner hours). Plenty of space and nice tables to eat at in store though. Plus free wi-fi.
I really recommend seeking them out. They are off Pease Street, toward the Grand Canal. Our dinners for 2 averaged around 20 euros (for 2 meals)
My DH and I will be there then, too! Here are four places on my list:
Winding Stair Restaurant, 40 Lower Ormond Quay, north of Liffey beside Ha'penny Bridge. (01 872-7320) Contemporary Irish food, high quality and good value. Nice views from window tables over the Liffey. Lunch and dinner served daily, 12.30-3.30pm, 6-9.30pm; a la carte; house wine from €24. www.tasteofireland.com/review.rvt/1194.html
Monty's of Kathmandu, 28 Eustace St., in Temple Bar. (01 670-4911) Dublin's only Nepalese restaurant. The chefs are all Nepalese. The friendly staff give advice on food choices. If you check out the following website, you'll be impressed with the awards Monty's has won, and the glowing reviews. You can take a photo tour of the premises. The menu seems similar to Indian cuisine. One food critic describes Monty's nan as "the best ever"! Quentin Tarantino and Bono have eaten there! Open Mon-Sat noon - 2:30pm, 6 - 11:30pm, Sunday 6 - 11pm. www.montys.ie
Half Moon Crepe Co., Crown Alley, Temple Bar. Comfortable and friendly Dublin café serving an assortment of savory and sweet crepes. Open 9:30am - 11pm.
Bewley's Café Bar Deli, 18 South Great George's St. at Grafton St. (677-1646) Pasta, pizza, salad, wine, beer. Coffee roasted on site. Open noon - 10pm. No reservations.
I live in Dublin and in terms of good, not too pricey eateries, I have several thoughts:
JoBurger (Rathmines) Excellent beef, chicken and lamb burgers w/ interesting combos, peri peri chips and a really funky vibe
The Farm on Dawson St. is new, organic and pretty reasonable (price wise) my wife and I visited recently and were impressed.
Fallon and Byrne off Great Georges St. have an excellent takeaway counter
All I can think of right now- I'll post more later when I think of 'em.