Clinton, because his election actually brought a national realignment. Obama couldn't have won in 2008 if Clinton hadn't in 1992.
1992 was not a realignment. If it was, WV, LA, AR, KY would still be voting Democrat.
1988 was a realignment.
1992 was a realignment because most of the Northeast and Upper Midwest have been voting D ever since. 2000 was only a regional realignment because the Outer South began shifting to the GOP nationally, but the rest of the country stayed the same.
By that criteria, if 1992 was a realignment then was so 2008 because of states like VA, NC, and CO switching partisan allegiances. Certainly there aren't political realignments every 16 years.
That's only two elections. North Carolina flipped back to the GOP in 2012. If Virginia and Colorado keep voting D in presidential contests, then we probably could call 2008 a realignment, but it's still too early to tell.