It sounds like you are set. Not sure what OS system you are working with- but Mac OS is THE OS that all great artists use due to the great creative software especially designed for music, film and artwork.

Pro Tools is great for editing; but also you will need FX enhancers to mix- amplifier to plug into your computer is needed too I started out using a $20 used Marshal guitar amp that I went to Radio Shack and bought $40 in cables/ converters to fit the one pin attachment into the computer. You can change gate/compression EQ on the editor software- so it is true about not soundproofing your home studio- BUT you have to have GREAT earphones. No amount of money can buy outro speakers for any computer and you can NOT rely on the internal speakers you computer came with. Spend your money on a good mic and good cans (headphones). I find good stuff at local pawn shops actually- look for these brand names: Sennheiser mics and headphones are the best; but can cost from $200 to 4000 each. If you to add monitors- external type speakers- then you are going to need at least $200 on those– Alesis are the best and range with a budget to real expensive. Then you will need to ADD to your hard drive – buying a memory chip card to expand your memory storage! Music files in editing mode take up SO MUCH SPACE – just a 3min song eats up everything because you are adding so many files of drums, guitars, vocals, etc. Go to any pro studio and you see banks of hard drives everywhere due to this one negative of doing everything on a computer. So save and get more cash just to update your computer’s memory. Keep with headphones- forget the noise you will bring in- be civil to your neighbors… Good luck.

Oh also- get some texts- online or at a library- about how to MIC if you are using acoustic real live instruments such as piano, acoustic guitar and vocals. Mic’ing correctly makes a big difference in your final project. If it isn’t heard; then what is the point. You can always bring levels down in the final mix/edit.
References :
google search with key words "home studio recording equipment" to find links for your PC/Mac compatible software