Around $1500 is a good starting point.
It's not necessary to spend that much, but I just put together a kit with a Roland TD8 (which may be much more than you need for your practicing) and Pintech Studio Elite for right around $1500.
If you plan on drumming for the rest of your life, you are better off with a mesh headed kit. The rubber trigger pads do the job well, but they'll destroy your wrists before too long.
I looked into building a kit from individual pieces and it really is FAR cheaper to pick up a package.
Actually, now that I think about it, Guitar Center (and lots of other places, check out http://www.gearhead-music.com and especially http://www.drumbalaya.com -- they took good care of me) has a Pintech USA Spirit kit with mesh heads and a TD6 or a TD8 for right around $1000 right now. Everyone is emptying their inventories it seems, so now might be a good time to look into it. The only thing I didn't like about the USA Spirit was the cymbals, but it's a great kit for the budget.
I've got my TD8 right here, but the kit doesn't arrive until Friday or Saturday. I'm going NUTS.