I had a single 10" in my Laser and it was more than enough. Don't just pay attention to PEAK wattage, RMS is the more important.
I just got some new Alpine o.e. replacements in my truck today, so far they sound great for just little 5x7's. For a deck I stick to Pioneer, their reliable, have good power, and lots of audio adjustment. Match your system to your car for the best sound.