A few tips I try to follow to keep my Nook Color running as fast as possible:

- Stick with CM7.2 (and not CM9).
- Use LauncherPro as your launcher.
- Overclock to 1200 MHz (you may want to undervolt as well to offset increased battery usage).
- Keep compcache disabled.
- Use 16bit transparency
- Disable surface dithering
- Disable 32bit framebuffer (Nook Tweaks)

I've used over a dozen launchers (ADX, ADX EX, GO Launcher, Zeam, Lightning, Regina, Trebuchet, Nova, etc), and I always go back to LauncherPro. Nothing else is as quick and smooth as it is.

Opera usually is the quickest browser (Mini or Mobile).

Instead of using a browser for everything, try to find a dedicated app for it (such as your favorite forum, social site, or news site).