(Core Duo MacBook with 2GB RAM)
I did an erase and install first off and Leopard was quick in most senses but animations seemed to be kinda sluggish.
I decided that i'd do the install again but incredibly pedantically...so it was:
Zero Out HDD
Erase & Install
Update
Restart
Install iLife '08
Update
Restart
Install iWork '08
Update
Restart
Install MS Office 2004
Update
Restart
Install all my other apps
Restart
And now I could swear it's running better, although it could be because I went through it like that so i've decided this is the best i'll get for now
I also decided not to install the DivX Codec since I heard it could be causing problems (put Perian on instead) and to turn off icon preview in the finder.
I'm not suggesting anyone to do any of the above, but it's made me happier