I also am having the same issues underlined in some of these replies.
I installed launcher pro, and it seemed to run much faster, except for some annoying jitter when I activate the launcher or scroll through apps. I suspect this will be addressed in an update, as my G1 was running CM6 with launcher pro, and it wasn't lagging at all.
Back to Sense 3.0. Yes, it does lag, even if ever so slightly, and yes, this is HTC's fault. Sense 3.0, although it adds a lot of eye candy, just doesn't handle the memory and processor efficiently.
On a phone with 768 MB of RAM and a dual core processor, how is it that Sense 3.0 seems to eat up almost all of the RAM and leave you with about 100 MB, according to the Task manager? This is some serious bloat.
I can't wait for some stable CM7 build to come out. HTC Sense 3.0 is nice, but I'm not sacrificing speed and efficiency for eye candy.