Unless it's some disgusting name or difficult to read (riddled with X's, alternating upper and lower case, "leet speak"), then it doesn't really bug me. I barely remember people anyways, much less names.
I don't really have a problem with numbers, although I do find it pretty damn lame when people stick 117 or 69 or whatever. And speaking of 117, I think what I find lame in gamer tags is when it's obvious that there's absolutely no originality or thought put into it.
That goes too all the Master Chief's and Solid Snake's and SSJ Goku's and ESPECIALLY the goddam McLovin's! I've met like ten of those guys, the movie wasn't even that good!
*composes himself*
Anywho... I don't even bother with those players cause they make it pretty obvious through their tags alone that they're either kids or simple minded.