When I was first getting into it, I went with a HTIB -- around $750 for a JBL deal from Best Buy (5.1, receiver, DVD changer). It was way, way, WAY better than just using the TV's speakers, and didn't break my budget. I still use the receiver, but have since upgraded to a universal DVD changer (actually, I still use the JBL, too, but just for CD's), and have bought all new speakers and subwoofers as money allows. If money isn't a concern, you can get better sound by going with an a/v receiver (Denon, Onkyo, Harmon Kardon are all quite popular just to name a few), and full range speakers (mine are Athenas and I've been quite happy with 'em but speakers are completely subjective -- just go around and listen to a million sets till you find something you like at your price point), and a subwoofer or two (I went with a DefTech Supercube and love it, but like speakers there's millions of options). Buying everything seperately just kinda gives you more opportunity to custom choose products that are better suited to your wants/needs/room/likes with the features you want and styles you dig. But it'll be pricier than an HTIB and require a little more homework and research and footwork. Any way you look at it you got oodles of fun in your future! Good luck and have fun.
Oh, and while there's no reason for staying away from JVC I wouldn't necessarily limit yourself to them just because that's the TV you bought. I own a Sony TV, and it's the only Sony product I have.