Some more: Geektool
I also like Geektool.
I have the impression it's no longer actively maintained, but it allows you to run shell scripts and project the output in locations on your screen. I have 3 separate scripts running: one that gives me a calendar, one that gives me the IP addresses for WiFi, LAN, VPN and what that is externally, and one that shows me the top 4 programs in terms of system utilisation (the "top" program with some parameters), but my use is pretty tame by what I have seen some other people do - heaps of scripts around to experiment with.
Count me in for a +1 for menu meters too, btw.
As for the recommendations:
Alfred: looked at it, but couldn't get on with it. Worse, spotlight is now working the same, it lost the austere interface I liked and turned into major screen overload. If you're looking for a local file, you're now quicker using the search in Finder.
Brackets: a bit late to the party, it's Adobe and it hints at sharing cloudy things. I'll stay with TextWrangler instead.
CrashPlan: umm, cloudy so not really my thing. It does enable people to at least do some backing up, but my money (literally) is on a paid product Carbon Copy Cloner as it gives me bare metal restore as I can boot up for that backup. Strangely enough, I have managed the same with ChronoSync, but that was because it was a challenge :).
F.lux: umm, OK, but I tend to get nervous around people that see no problem in advising people to jailbreak their devices without telling them about the security implications (which they do for the iOS version)
LibreOffice: a must. And a prime reason to question paying for MS Office (the main remaining reason is called Outlook). About the only weird thing I never got rid of was that it opened Draw when I drag an image into a document instead of dropping it into the document I'm working on, which is *very* irritating as I never use Draw (I use Pixelmator and Omnigraffle).
MplayerX: confusing as there is something that seems similar, but I prefer it over VLC (which isn't bad either, but especially mkv files seem to work better on MplayerX). It just really, really dislikes switching from dual screen to single screen - VLC has no problem with that.