The SenseUI 2.1 cab weighs in at 44 MB and takes like 7 minutes to install lol, but it is fully functional and fully uninstallable...
I'm trying to make as many things installable as possible.
The downside to that is it's pretty annoying having to install so many things, but the upside is that ROM flashes will be rare if you can just uninstall and install new updates as they come out. For instance, HTC Messaging, which everyone hates due to MMS problems.
As long as you are comfortable with sticking to a specific WM6.1/6.5 build for quite a while, then you will be good to go.