Ok Preface:
The best camera is any camera you can afford including a pencil if you've got the skills. Many great pictures have been taken with home constructed pin hole cameras that cost no more than the cardboard they were made from. But, if what your photographing doesn't want to wait around for you to setup and expose then you'll have to look for different options.
If you need a rugged/cheap/ and quality camera I think the Canon 20d is hard to beat. I have found people on craigslist selling their cameras mostly above market value. More likely to find a good deal on a well cared for camera on a photography forum like photography-on-the.net or fredmiranda.com If you are patient a good deal will come along. A Nikon D40 is another excellent choice.
As for lens selection, this depends entirely on the photography you want to do. A good lens, especially a zoom, will be much more expensive than your camera, but is also a good investment because lenses do not lose much value if they are very well cared for(and you keep a UV filter on the front end to avoid lens damage).
For general photography, you will love that 18-200mm IS lens from canon or nikon. If that's what you're doing then feel free not to read any more.
If you want to do specifics like close up macro, long range telephoto, extreme wide angle, or low light photography there are many other lenses to consider. Generally I know canon lenses much better so I'll stick to them.
Best cropped sensor(20d, rebel,etc) wide angle lens
Canon 10-22mm or Tokina 11-16 for canon
Macro(for extremely close up pictures of bugs, plants, or just a regular headshot type lens)
100mm 2.8 Macro
or
60mm 2.8 EF-S Macro (plus full body shots of people)
Low light value lens
50mm 1.8
Long distance Lens
This one is harder because the prices get astronomical. If you want to do bird photography, you won't be happy with anything under 400mm which will get you quite far on a cropped sensor camera. Great pictures can be taken with less focal length, but getting tight shots is much easier with all that reach.
Some good lenses for this is the 100-400mm IS 3.5-56 or 400mm 5.6, but they are both extremely expensive.
Again, used is the best way to buy. Definitely stay out of the Box stores, theres zero benefit from buying from them.
If you don't want to buy online, try Webb Camera in Philadelphia, I bought my camera from them.