Well, from what you have right now, I can't see cables making a difference. If you're making long speaker cable runs, then I'd suggest 12 or 10 ga, but other than that, your 14ga will do just fine. Some quality interconnects might help if you have have issues with interference. But, you're not going to hear a sound quality difference by upgrading cables (unless there is something seriously wrong with the ones you have right now).
For power conditioners, I'd say look into Tripp Lite, Furman, Panamax, and APC. You should at least have a surge protector on your system to make sure a thunderstorm doesn't fry your gear one night. Tripp Lite makes some pretty reasonably priced bar-style units that are excellent. You don't need a $2000 Balanced Power unit. However, good power conditioning can really help to keep the noise in your electrical lines from other appliances out of your system.
For cables (if you need new ones or longer lengths), I'd recommend that you buy in bulk and terminate them yourself. It can save a lot of money. For interconnects, something from Blue Jeans Cable or Impact Acoustics should do fine.
If you want to buy cable in bulk, then I'd recommend looking at Westlake Electronic or Parts Express. Westlake Electronic has excellent prices on Canare and Belden products. Parts Express sells Sound King wire, which is some nice looking, high-quality zip cord.