Sorry to hear about your speaker.
You're sure it's the speaker and not the connection? Any other troubleshooting done?
If you're going to switch, there are lots of threads around here about speaker options... BobL convinced me that the 50w Weber Blue Dog Ceramic was the way to go, so I took him up on it and I've been very happy. Since then, however, he's switched to the Weber California Ceramic, and that seems to be where he stopped. (
He breaks down several speakers rather thoroughly here.)
Maybe you know this already... but you don't need to match the wattage ratings of the amp and speaker. Different speaker wattage ratings will affect how they respond at different levels; if I were to do my Weber purchase all over again, I'd probably get a 75-watter because higher-rated speakers tend to sound fuller at lower volumes, but as I said I'm happy.
The idea of using speaker(s) with a lower rating is, I think, based at least partly on the idea that you can push them hard and get some additional breakup that way. I'm not sure I put a lot of value on that so much (can't play that loud very often); however, supposedly a speaker's power rating is actually half of what it can technically handle, and generally people won't be running their amps at 10 all the time anyway. So a working C90 should hold up just fine with the LSC... but not a defective one.
Anyway, let us know what you end up doing.