$5k wont get you a soundproof multi-room studio, but it'll get you a very nice start for sure. My studio space is one big open room. I think you'll generally get a better sound out of a larger space. I'd save some of those construction costs for now.
I'd start by allocating a decent chunk to acoutstic treatments- basstraps, rigid fiberglass, portable gobos, etc.
Say, $600ish . (Stay away from foam anything)
Soundproofing (not the same as acoustic treatment) can get VERY expensive depending on where your space is and what you're trying to isolate yourself from (i.e. footsteps from above, screaming neighbors outside, or neighbors that dont want to hear you). This could be boarding over a few windows, or layers of sheet rock on the ceiling and walls. Costs can add up quick ~
$0 to $100,000usd.
You'll also need...
Computer - Build a windows PC for ~
$500 or use the one you already have
Software- Reaper ~
$60 Awesome software
Interface- you need to decide how many channels you need and what quality you're willing to pay for. The most popular now are firewire based and generally have mic preamps on board. Spend
$500 ~ $1500+
Monitors- Don't bother if you aren't willing to spend over
$500+
Mics- holy shit, this could fill an entire bbs
. For drums, you'll want at least a pair of sd condensers for overheads, some nice dynamics for individual drums a good dedicated kick mic, plus a few for guitar cabinets and a decent ld conderser for vocals~ lets say
$2000 to start. You'll have plenty of time to add more mics to your locker as you go.
Add in cables and you'll be close to ~$5k.
...and in response to Dinty above- I wouldn't drop that kind of cheese on a Nueman if I was just going to plug it into a $100 Presonus preamp and route it through a 1010lt (I have 2 1010lt's btw). I think his priorities are a little out of whack.