I'm running 77 plugins, not including all the small patches merged into the Bashed Patch.
When I start up Fallout 3, before getting tot the main menu my cursor appears just before the second slide disappears usually. The cursor appears when your active mods are done loading. Without mods the cursor pops up when the first slide is still up usually. So the initial loading times are longer.
For loading savegames, it takes around 10 seconds, which isn't very long, especially with all sorts of texture replacers. But that's because I have 4 Gig of RAM and a 64-bit version of Windows XP.