The only two sitting US senators for whom I have actually voted are as follows:
John Kerry acu 5; aclu 100
Dianne Feinstein acu 11; aclu 78
(no, I didn't vote for Ms. Boxer or Mr. Kennedy. I kept waiting for someone to flame me when I posted that.) But seriously, I'm trying to think of what sitting reps won my vote. As nearly as I can recall, Capuano, Tauscher, and Frost. Though I think Frost lost his seat in redistricting. Let's see...
No, it looks like he's still there.
Frost 16/65
Capuano 5/85
Tauscher 13/75
And, yes, I have actually voted for Republicans for both US Senate (in MA and CA) and US House Member (in TX and FL). It's just that no Republican I've voted for has ever won in a US legislative race. The only people I have ever help elect to US House/Senate happen to be democrats. Though my own voting record is much closer to 50/50 for GOP/Dem than the above would suggest.