The guitar and amp will be the easy part. That's really just personal preference.
For recording...the sky is the limit. Are you hoping to do some nice demos or try to get as "pro" as possible?
Mac Pro tower : I like the flexibility of 4 easily swappable hard drives and the ability to add UAD processing cards.
API Lunch box with a small assortment of mic preamps and re-amping modules. I also really like the Avalon U5 for it's flexibility and cleanliness...for a direct signal.
Nice selection of mics...Royer, Neumann, Shure, Sennheisser...for micing cabs and acoustics.
Studio monitors...I found smaller mains with a sub work best in smaller spaces like yours and mine. Right now I'm trying out the Yamaha HS50s/HS10 and they seem to be working great in this small space of mine (10'x14')
Studio treatment : make as much as possible yourself. ATS Acoustics sells 2" OC703 for $59. In my 10'x14' space, I probably used around 16 boxes to build walls and bass traps. You'll still have to buy some low-end treatment (GIK Scorpus traps) to fix low modal ringing. When all is said and done, expect to spend a few thousand on room treatment.
Because I play guitar and bass, I rely on a variety of virtual instruments for other things...drums, vocals, keys, orchestra. I also have a nice selection of plug-in effects and utilities. In all, the plug-ins can cost more than some new cars. I like BFD, Ozone, Elysia, FabFilter, UAD, Omnisphere, VSL and many others.
Because I do a lot of work at night and don't have an isolated studio, I rely on a couple of preamps (a Kemper, a Line 6 X3, and a Voodoo Valve) to do silent tracking on guitar and bass. If you don't want to go the processor route, you may need to look at a Palmer PDI03, or equivalent, to pull a signal from your amp when the neighbors are sleeping.
interfaces : I use Focusrite and a Digi003. I'd highly recommend getting something with more than just 2 ins/outs. Having optical and SPIDF ins/outs has also been a HUGE help for me here. Whatever you do...make sure the interface is compatible with the computer you choose.
If you're doing software drums yourself, look at some sort of midi trigger/controller. Korg PadKontrol is nice. But a simple Maudio Keystation 32 works for me too.
I'm sure I have at least $1000 just in cables a signal routing in my "studio." Don't forget about all that little stuff that can chew away at your wallet.
There's a lot more...but these are just a few thoughts off the top of my head.
