Actually, that is probably about the smallest I'd recommend for speaker cables. With AWG, the smaller the number, the bigger the wire. I'd say for speaker cables you'd want somewhere in the 12-16 AWG range, maybe 10ga if you're really serious. Since that CAT5 wire has 4 pairs of wires inside, you'd end up with four 24ga wires per signal, which would be about 17-18ga. Effectively a little on the small side, but not too bad.
The Home Depot cable and CAT5 cable are the recipes I see the most. But you might also look into buying bulk speaker wire from name cable manufacturers, such as Cardas, Kimber, Audioquest, and Analysis Plus. You can find bulk speaker wire at Audioadvisor.com, needledoctor.com, DIYcable.com and ramelectronics.net. I used the Kimber 4TC for awhile and like it alot. Ramelectronics also has a variety of spades and banana plugs to use. You might also look into Canare quad speaker cable such as the 4S11 (huge -- AWG of 11 I think) or 4S8 (AWG of 13). I used the latter in my home office playback system with good results. You can get bulk Canare pretty cheap at markertek.com.
Also, I've really been enjoying silver-clad speaker cables in my playback systems. You might want to check with Nickspicks, I think he bought a bunch of raw silver-clad wire off ebay and might have more than he needs.
If you don't want to go the DIY route, I can certainly make you a pair of my Segue Doghouse silver-clad speaker cables. But I've also got an 8 foot pair of used Kimber 4VS speaker cables in the yardsale section. And I haven't listed them yet, but I've got a pair of Canare 48S quad speaker cables I'm going to sell. (Replaced both the Canare and the Kimber with my silver-clad cables.) The Canare 4S8 is currently a 15 foot pair, but I might break it up into an 8 foot pair and a 7 foot pair if you're interested in something shorter.