I just created a brand new site with a fresh install of 2.0.18. Install went fine.
But I'm having a couple strange bugs:
1) There don't seem to be any thumbnails/images. No logo image at the top of the default (or any other) theme (I have verified logo.gif is present in the themes/default folder). No thumbnail images for modules on the admin page (but the links are there - the menus pop out when I hover over the right spot).
2) Many themes (phpkaox, fiapple blue, fisubgrey) aren't showing the menus in a vertical column, just a wrapping list. (default theme seems to be fine). No idea if this is related to problem 1) but thought I'd include it in case since I don't have this problem on other sites.
Any ideas?