Help me choose my first DSLR

[photohack]

My interest in photography has been rekindled via iPhone and instagram. I'm now in the market for a DSLR and am keen for more control and quality. I still have an old EOS 50 film camera and a lens that I think I could use with a DSLR. It's a canon 28-135mm f3.5-5.6 USM zoom.

Currently considering:
EOS 650D $600 ish
EOS 5D $600 ish used
EOS 5DII $1500 used
Fujifilm X100 $850

my questions:
How important is the full frame sensor, other than giving me the desired focal length from my lens?
Should I just sell the lens I've got and start new?

Context:
I've been shooting anything and everything. Candid stuff with the kids, landscapes, trying my hand at street photography.

Thanks in advance for your thoughts.

 

[subscuck]

While FF is nice for the better high ISO performance, the newer generations of crop bodies have gotten better with high ISO, so I wouldn't rule out a crop camera. Be aware that the 5D has an AF system that leaves a lot to be desired. The 5D II is better, but still falls short. My advice would be go with the 650D. It's a very capable body that you won't outgrow for a while, and the kit lens that comes with it is pretty respectable. Not great, but certainly good enough. You can then start saving for better, non- EF-S lenses for an eventual upgrade to FF. FF will require good glass to get the most out of it. Cheap glass will show itself far more with FF than with most crop bodies. Your 28-135 is pretty meh, I don't see where you could sell it for any substantial money. The 18-55 IS kit lens will perform better.

 

[JohnTrav]

I think your best bet would be to go on ebay and look for a nice used t3i or 60D with a kit lens and start with that. Depending on your budget. A nice 7D would work well also. I would personally take a 7D over a 5D or even 5Dii just because of how fast the autofocus is. Its nice for when I am shooting sports or even kids running around just playing.