Yes, I can fully agree with ignatz. I like the speed of Google's servers (Agamai servers I think). Like with the search engine, it is very fast, even over dial-up.
Other than that, I love Gmail's keyboard shortcuts: hit ‘c’ for composing new mail, ‘n’ for next message and so on.
I could also live with the discreet text-only ads placed similar to the way they are in Google search results. Perhaps I wouldn't use Gmail for transmitting "sensitive" internal cooperate information. On the other hand, if I am in need of sending a full 700 MB .avi movie to some friend, Gmail might be a good way - given that my friend also has a mail box big enough to hold this kind of a monster attachment