New Camera Blues- 7D vs 6D vs ???

I am looking to upgrade in the next few months. Currently, am using a 30D-my first and only DSLR to date. I know, I know, it is long in the tooth! I am a fairly advanced photographer.I shoot a lot, mostly outdoors.

Things I like about the 7D--weather proofing, 100% viewfinder, ability to wirelessly trigger external flash. What can I expect in terms of improved image quality over my 30D? How about low light performance? I have always been quite disappointed with night shots with the 30D--star trails, etc--but am pretty impressed at what can be done with LR4 noise reduction.

Actually, I had pretty much settled on the 7d being my next camera--THEN Canon had to muddy the waters with the 6D! A more affordable full frame! Also significantly lighter/smaller than the 5D line-- a plus for my small hands and neck issues. But I lose the 100% viewfinder and weatherproofing. Not sure about ability to trigger external flash. Also concerns about durability in general and shutter life specifically.

Or should I just break the bank and go for the 5D II or III, and get used to the heavier weight?

I do want to stay with Canon, so please no suggestions to switch to Nikon. Otherwise, am open to all feedback.