LastPass is an excellent password manager with very good form filling capabilities. The GUI is awful, as you've observed, but for the most part with LastPass you don't need to interact with the gui -- it eats passwords and spits them out. It also has applications for most mobile/smartphone platforms.
I use Passpack, myself. It is basically the opposite of LastPass in that its form filling is inferior as it's strictly bookmarklet/web based with no native browser helpers. I can't automatically pull your username/password as entered. On the upside, a great deal of attention has been paid to its interface and its workgroup/sharing capabilities are unrivaled. The other up-side to Passpack is that there's an AIR-based app for it that can be used offline. Because it's a standalone air app, you canot use it to film forms automatically but it does give you access to your accounts offline.
In both cases, you have a secure web-based solution that is extremely portable in that you need only the Internet to use them -- no software, no thumb drives. Lastpass is probably a better fit for a roboform refugee, though, as you're no doubt quite accustomed to a browser extension automatically remembering your accounts and filling your forms.