It's okay while I'm using the same application continuously, or if I've just got Thunderbird and a few Firefox tabs open. But open iPhoto - which has the daft design of "reading" your entire photo collection on start-up rather than on demand - or PhotoStudio (Cannon's equivalent of PhotoShop), and it pretty expires.
And as for starting OpenOffice? Right now, there's 9.4MB free. Start OO:
14 seconds in, the icon stops bouncing.
27 seconds in, the splash screen appears.
1 min, 12 seconds, and the splash screen disappears.
1 min, 18 seconds, and I get a blank document window with a cursor.
I'm assuming most of that time is swapping stuff out to make space for loading shared libraries, but it's horrendous.