Replacement 15 watts and whats?

[playsthespace]

I have what I'm sure will seem like a stupid question to you guys. I play 200 shows a year, but when it comes to the electrical/technical stuff I'm a complete rah-tard.

I blew a 15 in an Ashdown ABM cab and am shopping for a replacement. I've got an Eden WT800 that is supposed to 440W per side, but most of these speakers (Eminence CB158 for example) are rated 300W. Is the 300W enough? The Eminence lists 300W under "power rating" but then it also says "Music Program 600W." WHAT DOES IT ALL MEAN, MAN?

I guess the next question is, which speaker should I get? I literally play Folsom Prison next to La Freak in my cover band, modern U2ish and Coldplay-ee worship at my church gigs, and old-school Ryan Adams style southern rock in my original project. I've got the aforementioned Eden, and I'll be running an Ashdown ABM 410 with the 15 whenever my back feels good enough to drag two cabs out.