On daily basis, I use:
Gmail... K9 Mail would be cooler if it only allowed searches over the server. To my knowledge, only Gmail offers that.
Note Everything: by far the best note taking app I have found on Android. Its only shortcoming is syncing, it uses a separate app which imports/exports documents with Google Docs. Not as good as Evernote in this regard, but much better in every other way.
Widgetlocker: proud to have paid to this app.
Canabalt HD: finally ported from the iPhone, the game really deserves to be played, it's lot of fun for the go.
Swiftkey X: I keep it on even when using the hardware keyboard (ie, most of the time): it improves typing precision and I like suggestions to show up, especially when I type in English. I have obviously disabled auto-completion.
Neutron MP: wonderful music player. It was very heavy on my single core Droid 2 Global, now it's just perfect and smooth. The interface is 10 times better than Poweramp in my opinion. The audio algorhytm does something, during resampling music to 32 bit, to make music sound its best on our devices. To me the Samsung Captivate Glide sounds very good and it's much much better than the Motorola, which sounded so-so even with Neutron.... The Captivate Glide + Neutron convinced me to buy a 64 GB sdxc card today: it will be my portable music player, no need for a separate device. Using it with Audio Technica AD2000 headphones in a park, right now.
Opera Mobile: I have frozen the stock browser to keep this one only.
Titanium Backup: to freeze apps.
Osi rom: I like it very much and it's not strongly themed.
Sony Xperia S launcher: very elegant, clean and quick. Its Icon pack is also a bit better than the stock one.
The file browser coming with Osimod is really wonderful, it won me over my former favourite, Root Browser.
This is not a daily, but:
Tiger Arcade emulator: I will have to try to play Street Fighter III Third Strike with it.