In an effort to continue my occasionally useful posts, here
5 addons every player should have that you may not know about...
(all links go to curse)
1) Align-> puts a grid on your screen for lining everything up just so. I can't find it on curse, but it's rather out of date anyway. As in I'm not sure it's been updated since before Cat. Here's another one that does the same thing, but updated for 4.2
2) Healers have to die->Okay, you're wondering why I put a PVP addon here. It's so much more than a PVP addon. If a mob's healing, you'll know it. If you're in a group and your healer gets attacked, you'll know it. Sure, it's nice in PVP, but it's just as nice in PVE. It is a tad spammy in raids, but there's probably an option to fix that, I just haven't looked.
3) GTFO->makes noise when you're standing in owie. Brilliant and simple, and useful in all content.
4) Multishot->automatic screencaps of achievements, raids, all sorts of things. Any screencap you see on this blog was probably taken by this addon. You may want to change it from the default options, as they're the reason I had over 4000 screencaps last year.
5) BadBoy: Anti Spam Automatic Reporter-> Because gold farmers are really really annoying.
And 5 more that are awesome (and you may or may not know about)...
6)Gnomish Vendor Shrinker-> instead of those huge boxes, you get a nice compact list. Again, brilliant and simple.
7)OmniCC ->because having the cooldown countdown on the buttons just makes so much sense
8)Tidy Plates-> because the default plates aren't that good, and tidy plates shows you your dots, whether you've got threat on a mob or not, and manages to do that while looking pretty.
9)Bimbo-> Marks gear that's missing enchants or gems. Again, simple quality of life addon, and the second Tekkub addon on this list. He's good at making simple quality of life addons.
10)Quartz-> I've been using Quartz so long that I don't even remember what the base casting bar looks like. It's very customizable and shows you your lag, which is a big help in getting as much as you can out of your toon.