More options for clock, weather, battery, and toggle widgets. Downloadable skins, so new skins are frequently added. If you like the stock widgets, it's not needed. If you want your phone to look a bit different, good choice.
If you prefer a nice simple clean look for your clock / date widgets, this is a good choice. I think I see more people ask what app does this in screenshots than anything else. Similar to Clockr with more options.
Best live wallpaper for the Thunderbolt. It's basically the startup screen with lightning as your background.
Easy way to create subfolders with a custom icon on your homescreen. There are four types of folders: Applications, Files, Contacts, Bookmarks. The thing that makes Smart Shortcuts unique from similar apps is that it also has a "Freestyle" option that allows you to combine folder types (example: mix bookmarks with Apps).
This badly named free app has one of my favorites "looks" for seeing a call log, text message log and upcoming calendar events. It's a 1x4 widget, so very space efficient.
Replaces the default Car Dock app with something a little more robust. I wish it had widget support, but other than that -- it's a pretty great App.
By the maker of Tasker, this app allows you to create your own widgets. Very customizable. Since this integrates with Tasker, you can make some pretty amazing custom widgets.
I haven't been impressed by a phone app in awhile, I have 211MB of free space in data/app and 47MB free in system/app but I don't keep a lot lying around - Maps, Car Home, Navi, Music, Live Wallpapers, Calculator, Email and all that jazz.....gone
...as far as Market apps - I barely have 15 installed, Tapatalk, FB, Twitter, SetCPU, NinjaMorph, Gmail, Better Terminal, Screenshot ER, Root Explorer, Dropbox, TiBu, Wireless Tether, Swype and SyncSMS - that's it