I was disappointed by the lack of good towns in Fallout 3.  Fallout 2 had great towns to explore and quest from.  Towns like Vault City, New Reno, Klamath (sp?), and so on. Fallout 3 didn't.  The best town it had could be blown up in the first couple of hours of the game depending on what kind of character you were playing.  The second best was Rivet City, which was kind of meh.  There were places that had potential to be good towns but only had like 5 people living there.  In the end, Fallout 3 seemed smaller in scale than Fallout 2 which was the game I couldn't help but compare against when I was playing.  And whenever I made the comparison, Fallout 3 didn't compare well at all.  
 
I hope that Obsidian puts in some cool towns in Fallout: New Vegas.  But I think deep down, New Vegas couldn't possibly have the scope that Fallout 2 had.