Audio newbie seeks system advice

Hello--

I'm new to this world, but enjoy good sound and am trying to cobble together a nice little system. Here's what I've got so far:

- Outlaw 1050 receiver/amp (bought new)
- Sony DVD/CD and MD players (nothing special)
- Snell KIIv's as fronts (used)
- Snell HCC-500 center channel (used)
- Snell PS10 powered sub (used)
- Monster Navajo speaker cable

I'm hoping to complete the home theater setup either by getting a pair of decent, reasonably priced (probably used) Snell surrounds, or by using the KII's as surrounds and getting new fronts that aren't so large that my girlfriend will boot me out. (She's already less than thrilled about the new TV....)

Any recommendations? I assume that getting Snells would make the whole thing most likely to sound together? Does speaker cable really matter? Given the rest of the setup, would I notice much of a difference if I got a nicer CD player?

Any advice much appreciated.

Thanks!