Honestly, I would always go for Cyanogen. They are very diligent about keeping bugs out and keeping them updated. Cyanogen comes loaded with lots of OS improvements such as custom kernels and smart processor clocking, some basic menu structure enhancements and unlocking features of the device that were unavailable before. They also update some basic apps on the device as they come out with new releases before official releases are available, e.g. the new Gallery app (factory). Basically, Cyanogen will be your speed but the eye candy will be achieved elsewhere.
As far as the eye candy goes, you're obviously going to look for a new home screen. I've gone through countless in my experience working as tech support, and hands down the overall best (and quite fantastic) is "GO Launcher". It's available for free from the market. When you get it, PLAY! Play around with the different settings it has to offer and you'll find something that fits you perfectly. I'm on Cyanogen 7 on a mytouch3g slide with this launcher and it is FAST and has NEVER crashed. Ever.
These two in tandem guaranteed will make you a happy individual!
