SPL=Sound Pressure Level...usually for people who like rap
I use a 50/50 set-up because I listen to everything.
For your type of music I would go with a sealed enclosure (not ported or bandpass). Sealed enclosure are more "accurate", have a quicker response (better for drums) and are not as "boomy" as ported or bandpass enclosures. I would go with a single 10" or 12" subwoofer. Here are a couple of great web sites to look.
1) Sound Domain
2) Just Woofers
3) Just Amps
I got my sub from Just Woofers. You can get a pair of JBL for $140. That's what I got, because a single would cost $100. I figure for only $40 more I can get the second one. A very similiar sub to the JBL is the Infinity Reference. With going with only one sub, you can get a lower powered two-channel amp and bridge it to one channel. For example, the amp that I am using is rated at 75x2 RMS, but when bridged it's rated at 200x1 RMS. This saves money by not only having to buy one sub, but you'll save money by buying a less powerful two-channel amp.
As for the other speakers, Bostons are good, Infinity, MB Quart, Diamond, to name a few. For head units Clarion is excellent!
Feel free to email me with any questions also.