The main differences between a home set up, and a recording studio are
1) microphones
2) quiet recording floor
If you purchase a pro tools setup, the A To D converters will be decent enough in the 192/003 interface of the Pro Tools hardware to do a good job. The other thing to consider is noise while you're recording. You don't want to be interrupted by the ice cream truck going by, or your mom yelling that its time for dinner ;)
Keep in mind, this is only a concern when you're using microphones for recording, and not a DI (direct input) with your guitar.
Many DAW's can record your music equally well, so the main purpose for going with Pro Tools is the editing, and processing capabilities, mixing your track with automation, and creating a stereo mix of your song.
Beyond microphones, and a quiet floor to record on, the other benefit you'll receive at a studio is (hopefully) and experienced operator to take care of the technical stuff while you do what you do best.....play guitar.
I realize I've jumped around in this answer a little bit, sorry. I work at a studio, and have been using Pro Tools for about 15 years. If you have any more questions, feel free to get in touch, and I'll help out as best I can.
