Stewart, I feel your pain. This is what it’s like with KDE’s Kmail (part of Kontact):

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
10134 csamuel   16   0  337m 236m  28m S  0.0 23.3   2:32.73 kontact

That’s for a 685MB mail directory..

On a slightly related tangent, you may be amused by Alec’s splashscreen rant which makes a lot of sense. I guess they’re there because of the novice users who assume because they don’t see anything instantly then they should start the program again… and again… and again.. and then wonder why their machine has turned into a thrashing writhing wreck and 52 different windows are appearing very, very, slowly…