A few mods I recommend. I usually take the utility mods more then the combat helping mods.
Outfitter - Able to switch gear quick and easy, works very well later on when you start mixing gear due to Duel-Spec. Even has some auto-switch settings, I right now have it setup so when I change my spec I switch my gear, have it switch to my prefered "Championing" tabard when entering a heroic instance, etc...
GroupCalender - Just improves on the default calender in pretty much every way possible, so much more clean and streamlined, and a lot more features.
AkisRecipeList - Basically if you have a profession and want to max it out, this will take a list of all known recipes in the game and match it with all the recipes you already have, giving you a list of what recipes you are missing, and how to get them. This is also nice because it lets you look at all of them and figure out which ones you may want to strive for.
If you want to get a little more complicated...
PowerAuras - This mod is one of my favorites. It allows you to create a graphical image that you can place anywhere on your screen for specified events. As an example, on my hunter I want to know when Lock and Load procs, and how long I have til it expires so I can fit it in my rotation correctly. I have it setup so a graphic appear over my head with a countdown timer counting down the buffs duration. This is invaluable once you start having things like "procs" without having to look up at the buff bar. The only issue is it takes time to setup, since it's completely customizable.
I also recommend learning some macros. They can be great. You don't even need to really use macros for combat purposes, but maybe just to make your action bars a little more manageable. My mage right now has it so all my "Teleport" spells are in a row on one bar, but they automatically change to "Portal" spells while in a group. If I am in a group but still want the teleport, I have a variable that allows me to revert back to teleport spells using the Shift key. I have the same setup for my food/water, the main button is the water so I can click it to drink, but when I run out I hold shift and the button converts to the conjuring spell to make more.
Oh, and I am definitely making a Goblin. I just don't know HOW right now, since I already have one of every class in the 50+ range at the lowest. Hoping Cataclysm changes the old world enough that I can stomach leveling up a duplicate class, also, I need more character slots! I have considered just converting my tauren druid over to a troll, and then later on converting either my warlock or priest into a goblin.
Worgen are still up in the air, don't play Alliance much these days.