Computer Anonymous - Cardiff
Read The Overview if you haven't already, especially the code of conduct.
At the moment we're investigating to see how much interest there is for a Meeting in Cardiff. Once we hit a critical mass (5 is good, right?) we'll start looking into dates that work for all. If you're interested in coming, either fork the repository, tweet me at @sgsabbage, email me at: my twitter handle AT gmail DOT com, or find me on the ##computer or ##computer.cardiff IRC channels on Freenode.
Urban Tap House - I've heard nothing but praise for this place, though I don't know what it's like for groups to meet up.
Milgi - It has a yurt! Also, a lovely environment, heated garden, hot drinks, vegetarian and vegan food.
A Shot In The Dark - Well-known independent coffee house on City Road. Again, very nice atmosphere, free wifi, large upstairs with comfortable sofas.
I've just added a few to get us started, but if you have any favoured venues that aren't on this list, let me know, or fork the repo and add them!