depends what you are going to take pictures of. For example, I hike alot and am outdoors for most of my shots, so I decided early that I wanted a camera body that would be able to withstand the wear and tear I give to my equipment as well as the dirt/grime from the environment I'll be in. For me, the Pentax cameras were the ticket. I started with a K7, which had a full magnesium body which is fully weather-sealed. Just recently I sold that body and upgraded to the Pentax K5 and have no regrets. I also like the fact that it has a K mount, which has been used on Pentax camera bodies for roughly the last 30 years. Basically, I can buy a cheap lens at a yard sale and it'll work on my K5.
Like I said, it all depends on what you are wanting to shoot... decide that, then start looking at what will suit your needs.
Good luck!