Since you're a junior in HS, it seems like you have some time to build up before your college debut

It might be best to not get everything right away and leave yourself and upgrade path. Even just getting a receiver and a pair of speakers would be an excellent start and you'd be on your way to an excellent surround system eventually. If you know this is something you're interested in and want a quality system, building up a great system slowly is more cost effective in the long run than getting a cheaper 7.1 system to start with and then wanting to start all over to upgrade the whole thing.
You can certainly get a HTIB solution like the Onkyo one, but with $800 you can do better, especially if you don't get a full system right away.
Would you be willing to go used at all? A refurb receiver can save you a lot vs going new. At close to $350 or $400 depending on where you get it, a Denon 1706 would be a really big hunk of your budget.
Panasonic's digital receivers at around $225 are supposed to be a nice solution for a new budget receiver. You could get a Pioneer 515 new for under $200 or something refurb from Onkyo for under $200.
Assuming you'll get the Panasonic receiver and a Dayton 12" sub (you just missed the deal for $120 shipped, now it's back up to $150 + shipping) that would leave you with about $530 for speakers.
I think if you called partsexpress you might be able to get them to pricematch the old deal for $120 free shipping on the 12" sub. If so, that would help out a bit for the budget.
The most important part of your system is going to be your front three speakers. If you're doing mostly music, getting quality front stereo speakers is going to be the key. If it's mostly DVD watching, the center channel is where the vast majority of the sound comes from.
Before you buy something, listen to some different options. There isn't a correct answer for everyone, this is a personal preference thing.
Some stuff that would be easy to get a demo for would be Paradigm, Infinity, JBL, Klipsch, Polk, etc.
With $500 for a 5.0 set that's $100 a speaker which is not going to give you a whole lot of options. If possible, just getting the front three or even just two for now would give you a lot more options.
There are some nice deals online as well. Just about everywhere you're going to have a nice trial period and if you don't like it, you'll be able to send them back (if you have to pay shipping both ways, one way, or at all will be dependent on the place). For example
Aperion Audio will pay shipping both ways for you to demo.
Axiom Audio includes shipping in the price, so essentially you just have to pay return shipping.
Ascend Acoustics you'd have to pay both ways.
There's three internet brands all starting with "A" so you can see there's a lot of options out there
