and they don't nag for donations either. I use both and find them to be quite adequate. You can install a mail icon in your Firefox toolbar and jump in and out of it while browsing. Firefox is, for me, quite stable and renders the great majority of web pages well. These programs are small to download and will import settings and bookmarks from many other programs to make using them instantly a breeze. There is no trial period. You can install and keep them or remove them at your own will.
I am currently using IE & Outlook express. I would like to download Firefox & Thunderbird and try them out. My question is, can I download these two and use them for a trial without uninstallling IE & OE and without messing anything up with my original configuration.