Weight lifting/strength training at home?

If you're just starting out, I highly recommend getting a bench and a set of Powerblock adjustable dumbbells (http://www.powerblock.com/blocks.php). They occupy a small footprint and basically replace a whole rack of dumbbells. I got great use out of mine for a couple of years before upgrading to a power rack and olympic weight set. Still intend to blend the dumbbells back in for assistance exercises.

P90X- and you may need to get resistance bands. I'm in my 2nd round.

Get a used Olympic bench and weight plates with 1xstandard 7' bar and 2x 14 inch bars for curling... etc... I got around 400lbs and a bench for 170 from Craigslist.

I use an exercise ball and dumbbells right now (and a mat) - I'll need a bunch and a standard bar when my weight needs go up but you can actually get pretty far with just the ball and dumbbells if you have some of that handy already.

I put my back on the ball and my feet on the ground and hold my stomach level (relatively) while I do things like flys, chest presses, etc. Works pretty well and its actually a good core workout too (since you have to hold yourself steady). Would be a disaster with a 7' bar if you rolled off though, so I don't recommend that