As much as we like to put new software on old machines, sometimes they just can't take it - you wouldn't try to play Crysis on your grandmother's 98 HP, after all. That's why we're so glad that the CyanogenMod team is continuing to support its Gingerbread build, CyanogenMod 7, with an updated release. Version 7.2 has hit Release Candidate 2 for dozens of devices, and given the team's previous work that means we're not far from a "Final" version.
In addition to adding a healthy dose of Android phones to the list of officially supported devices, most of which come from Samsung, LG and Sony, there's a ton of new changes added in from community developers. A few of them are even backported from Ice Cream Sandwich and CyanogenMod 9, like an ICS dialer, various animations and telephony fixes. You can see all the new goodies in the oficial changelog - my personal favorite is ADB over network.
As with any custom ROM, consider your warranty kaput the moment you flash it. CyanogenMod 7 has been under near constant work for a year, so it's incredibly solid (much more solid, in fact, than many of the official device ROMs it replaces) but you're still taking a risk. If your phone can't run Ice Cream Sandwich effectively, and that should include anything made before the Nexus One or with lower specs, give CyanogenMod 7.2 a try.