Client software, that is. And you should too, if you use more than one computer (or ever plan on reformatting or buying a new one). I think Joel may have had it right: web-based apps do suck, but not necessarily enough to outweigh the advantages for developers and users alike. So let me plug a few web services I like, which you may also find useful:
Bloglines, which will spare you having to read several hundred backlogged headlines each time you switch machines, if you subscribe to lots of RSS feeds. There is a handy notifier for Firefox, and system-tray notifiers for Windows and Mac OS X.
Spurl, which offers a passable imitation of a real bookmarks sidebar, as well as a handy Firefox plug-in. Use live bookmarks to add your online bookmarks as drop-down folders in your bookmarks menu for extra nerd points. Or try del.icio.us if you don't need to import existing bookmarks, don't need folders, and don't need to mark links as private.
Gmail, which will damn near pay you to sign up anymore, and has even been kind enough to refrain from sending a CIA death squad to my house in the middle of the night.
Flickr, which I haven't used, but it seems cool and I need to pad out this post. It appears they've ditched their massive Flash-based environment, which is nice of them. I don't really think the internet needs yet another protocol for heaving text around.
...which is something that actually sort of annoys me in general, but I won't get into right now.