Been shooting for over a decade, owning various Pro Nikon bodies and switching to Canon two years ago (I think that's right). Anyways I love the XSI, but I am ready to invest in a new body, though to be honest I am having trouble deciding. Been reading reviews and thinking about the decision for over 3 months now. I only own the XSI and the 50 1.4. Here is what I have so far:
Canon 5D Mark II - I mostly shoot portraiture and the price is right, that being said I question whether this body is in all honesty worth $1800 over my XSI, so from a value stand point I really am having trouble justifying this one.
Canon 650D. The new Rebel has a lot to offer over my XSI. I do wonder whether the image quality is a step forward or back at lower ISO ?
OM-D EM-5. I have used Olympus PENs in the past and really love them. It's expensive but It's definitely on the table. As I shoot portraiture (mostly my kids) I am worried about the DOF of the smaller sensor being an issue.

(24Lii, sigma 50A, 135L), and for the other ends of the spectrum, sigmaEX 14mm2.8 and sigmaEX 100-300F4.
