I don't want to make too much of this -- it's likely that at least a few incoming Republicans will be on the moderate side -- but take a look at what's happening to the GOP conference. I'm working from Simon Jackman's ranking of Senators by ideology based on their voting records....going back to the beginning of the (current) 111th Senate, here's the score, working from the least conservative Republican.
3. Specter (ranked based on votes as a Republican): party-switched, started voting as a mainstream Dem, defeated in the primary.
4. Voinovich: retiring
5. Murkowski: probably defeated in her primary.
6. Bond: retiring.
8. Mel Martinez: resigned.
11. Gregg: retiring
12. Bennett: defeated in primary.
By the way, LeMieux (retiring) is next after Bennett; on the other hand, Scott Brown, who isn't going anywhere for a while, fits in between Voinovich and Murkowski. Still, that means that the next Republican down (Hatch) moves from 13th most conservative to 7th, pending the addition of any new moderates.
Of course, if the GOP does win a landslide in November, then a few moderates will probably be elected as well: Fiorina in California would I assume be to the left of Hatch. I'm not sure who else; perhaps Ayotte in New Hampshire? And I have no idea how McMahon in Connecticut would vote in the unlikely event that she wins -- plus, it wouldn't be a shocker if one or more other newcomer turns out to be in the Alexander/Hatch wing, rather than the DeMint/Coburn wing. Still, seven (with Murkowski) of the twelve least conservative Republicans from the beginning of the 111st Senate will be gone, and unless Vitter or Burr loses only two from the rest of the conference are on their way out -- Bunning and Brownback.