[Jorge]

I believe that we'll pick up seats in Georgia, North Carolina, and South Carolina, and retain most of our other seats, so that this will we can overcome a Specter loss.

If that's the case, then I would love to see Specter gone, even if it means a PA Dem takes his place.
My only real concern is that the Republicans retain their majority in the Senate.

[WOSG]

It is highly unlikely that Specter's winning would mean the difference between having the senate in GOP hands or not. Most likely the GOP will net gain a few, how many depends on how good november is for us... the odds of the PA race being in the margin are miniscule, and in any case Toomey is more electable than Specter so if that is the concern you should vote Toomey.