Dublin Inns?

Travel Info
Can anyone advise, from personal experience, on good and cheap hotels/BnB in Dublin, Ireland? We are a couple looking to tour Dublin for 3 to 4 days and we are looking for a guesthouse costing around 50 euros/night.
We have identified some guesthouses from tripadvisor.com, such as Egan's house, ABC guesthouse, Willowbrook B and B...but can someone please help us out here...

Travel Tips

ABC House BnB- a friend of mine stayed here for a European Honeymoon. It's close to downtown and the food was supposedly fabulous:
http://www.abcguesthouse.com/

Bushfield House is quite gorgeous
http://homepage.eircom.net/~bushfield/in...

The Glen Guest house is also downtown:
http://homepage.tinet.ie/~theglen/...

The Almara has won awards and is near the airport and the city:
http://www.almarabb.com/index.htm...

Others
if tripadvisor recommend them you should be fine. I've never had any trouble at all with their recommendations. ABC is quite far out of the city, so is Willowbrooks, so if you want downtown action they aren't good choices. They'd be a 20 min bus journey into town. Look for the postcode Dublin 1 or Dublin 2 (nicer) if you want to be downtown.
Glenn na Smol is a good B&B on Howth a nice small hotel on Howth is the Coach House. I have stayed in both places several times. Howth is a 20 minute ride into town on the Dart.