The dwarves, because they are merry lads, and I like the dwarf talk, but I played enough dwarf lately, so I chose another race. It is not only a question of bonus, it is a question of roleplay too. I find it fun to play a dwarf, even if my dwarves are a bit too near of the stereotype.
And I must tell, I find, personnally, the best Rogue (read dungeon delver type) are the dwarves. The Stonnecunning give them a edge to find traps, the +2 saves vs. poison help them against poison traps, +2 vs. spells against magic traps. The +2 Con gives them more HP, so they can sustain more damage (d6 is not a lot when you need to bracket someone to have decent damage), the charisma is not important for that kind of Rogue. The +2 work with stone and metal can be usefull when you have a trapmaker (That was the concept of my best rogue I have played yet, but Rinaldo start to perform...). The only lack they have, it is their speeds, but boots of Striding and Jumping can be bought at level 6 or 7, so it is not dramatic.