I very much doubt he's looking for or even wants headphones. He's a self-declared "basshead", which probably means he really loves the upper bass/lower midrange thump along with low end rumble, can't get that with phones.
@OP:
Going with a AVR will be your best bet, it solves certain problems and is generally easier to deal with. If money is tight for buying everything at once, just start with the sub and a pair of speakers. Cost wise, it really depends on what you want out of your system. Here's a couple of suggestions:
You can get something like the
Energy Take Classics or
Monoprice's 5.1 (10565) (which is essentially the same as the Energy's) and just switch out the sub for the BIC. This gets you 5 decent satellite speakers for you to use. So, with a $200 AVR you're looking at $650-$750 total. This isn't a bad setup, there are people who run this with their home theater and are quite happy with it.
Another suggestion would be to get
NHT SuperZeros. They are priced at $100 each, but they sometimes have B-stock (look in the clearance section) that go as low as $69ea. So, anywhere from $350-$500 for 5 speakers, but are definitely better then the Energy/Monoprice speakers, additionally these speakers are known for their excellent nearfield attributes. These would be my suggestion, and if it's something you might consider I'd suggest contacting them, they may offer a little bit of a discount on 5 if you purchase them at the same time but at the very least, it's something you can build over a few months.
So, why the AVR route? First and foremost, bass management. Pretty much all consumer level sound cards/software has terrible bass management if any at all, it's just easier and better to use an AVR. Another thing, room correction software is increasingly found in all but the lowest entry level AVR, this can definitely be a bonus. Also you mentioned wanting a control dial for volume, this is the best way of doing it plus it gives you various inputs to use and a headphone jack too.
If you don't want to go with an AVR you have the option of using active speakers, these are self powered. Popular brands include M-Audio, Audioengine, Behringer. Personally I'd opt for
Emotiva's Airmotiv 4s, though I believe it's currently out of stock right now.
As for the sub, to give you another option in the $200 range there's the
Dayton Sub-1500. But, given the description of your preferences, I'd suggest a better sub than the F12. For $329 you can get the
Hsu STF-2 which is on another level, it's one of the best under $500 subs out there and is probably the best value for the money for subs under $500.
A word of note though, this sub starts to fall off at 100hz, this means that the take classics would not be a great fit since their fall off is at 115hz, you could still use them and probably wouldn't even matter any since I'm guessing you'll run the sub a little hot compared to the speakers anyways. Just wanted to mention it though.
You didn't really specify a budget other than cheap as possible, certainly there's cheaper ways to go than this that will work, there's a whole mess of speakers that are under $200 per pair vs the NHT's, could go with 3 pairs of M-Audio AV30's for $270 total without the need for an AVR. Kind of depends on you.
As for my suggestion, I'd go with an AVR, the SuperZero's, and the Hsu sub. I doubt you'll ever feel like you need to upgrade anything unless you start using it for movies and even then it's a good mid range HT kit. It's about $1000 or a little bit less, but you don't need to buy all 5 SuperZero's at once.
One last thing, if you do go with an AVR if you won't be using PC->AVR->Monitor via HDMI, you'll need to use spdif using either optical or coax digital. This will require you to have a sound card/MB that supports Dolby Digital Live or DTS Connect in order to get 5.1.