I am using Helix Launcher, which seems less laggy and less failure-prone than the other home replacement apps I tried (GDE, Home++, PandaHome). It allows 1-7 screens and gives you 4 persistent icons at the bottom of the screen (I set mine to phone, gmail, browser, and maps). It worked fine with 2.0.1 stock, and now is working fine again with 2.1 (forced manual upgrade).
But for those not interested in third party homescreen replacements abcOrganizer or AppOrganizer provide a way to access categories of applications (and bookmarks and contacts; abcOrganizer, get it?) from a single user-selected icon on the homescreen. Frees up a lot of screen real estate.
It does, of course, require that you touch the icon on the screen which opens a panel of the included applications, but since you'd have to swipe over to another home screen for anything not on your default screen, it's relatively efficient.
I just downloaded Launcher+ from the marketplace and so far...AWESOME. All i wanted was a couiple extra screen and it delivers. No added wallpapers or widgets. Just a basic addition of home screens. Very pleased.