I am considering buying a 5.1 or 7.1 speaker system.

Currently I own a rather cheap (1000 dollar range) laptop whose sound card doesn't support 5.1 or even have 5.1 inputs, so I am planning on getting a USB external sound card, then getting a 5.1 or higher speaker system connected to it. My budget is anything less than 300 dollars (combined, with the sound card and speakers) but preferably under 150 dollars (willing to spend slightly more). This is where you guys come in, because although I'm no audiophile, my life revolves around my music and videos and that's not about to change any time soon.

Any suggestions on the sound card and speakers?