OT: what good web email clients do you recommend?

[joe at actionline.com]

Are there any good (simple/uncluttered) web email clients that allow
personal customization to simplify?

For a long time I have mostly used squirrel mail (now called
Ensignia mail) but recently I've begun to have problems with
formatting and font disparity (some too huge, some too tiny). These
problems did not result from any changes that I made, but apparently
changes that squirrel/ensignia made (for the worse).

I use gmail as an alternative, but it is way to cluttered to suit
me.  I prefer clean, uncluttered, and simple.

I have also tried to use mail2web, but it is cluttered with
advertising.

Any suggestions?