It looks like the Democratic Party will be a few Senators short of a filibuster-proof majority (60). So here's a list of Republicans Senators up for re-election in 2010 (19 out of 34 Senators who will be up for re-election in 2010 are Republicans):
Specter, Arlen (PA D+2) - born 1930; won 53% of vote in 2004; first elected to Senate in 1980
Gregg, Judd (NH D+1) - born 1947; won 66% of vote in 2004; first elected to Senate in 1992
Grassley, Chuck (IA R+1) - born 1933; won 70% of vote in 2004; first elected to Senate in 1980
Voinovich, George V. (OH R+2) - born 1936; won 64% of vote in 2004; first elected to Senate in 1998
Martinez, Mel (FL R+5) - born 1946; won 50% of vote in 2004; first elected to Senate in 2004
Bond, Christopher S. (MO R+7) - born 1939; won 56% of vote in 2004; first elected to Senate in 1986
McCain, John (AZ R+10) - born 1936; won 77% of vote in 2004; first elected to Senate in 1986
Burr, Richard (NC R+12) - born 1955; won 52% of vote in 2004; first elected to Senate in 2004
Vitter, David (LA R+15) - born 1961; won 51% of vote in 2004; first elected to Senate in 2004; "DC Madam scandal"
DeMint, Jim (SC R+17) - born 1951; won 54% of vote in 2004; first elected to Senate in 2004
Isakson, Johnny (GA R+17) - born 1944; won 58% of vote in 2004; first elected to Senate in 2004
Bunning, Jim (KY R+20) - born 1931; won 51% of vote in 2004; first elected to Senate in 1998
Thune, John (SD R+22) - born 1961; won 51% of vote in 2004; first elected to Senate in 2004
Brownback, Sam (KS R+25) - born 1956; won 69% of vote in 2004; first elected to Senate in 1996
Shelby, Richard C. (AL R+26) - born 1934; won 68% of vote in 2004; first elected to Senate in 1986
Murkowski, Lisa (AK R+27) - born 1957; won 49% of vote in 2004; appointed to Senate in 2002
Coburn, Tom (OK R+32) - born 1948; won 53% of vote in 2004; first elected to Senate in 2004
Crapo, Mike (ID R+39) - born 1951; won 99% of vote in 2004; first elected to Senate in 1998
Bennett, Robert F. (UT R+45) - born 1933; won 69% of vote in 2004; first elected to Senate in 1992