The fact is, you are always going to have memory problems if you have less than 1GB of memory. My system had 512mb when I first started playing and walking through Orgrimmar was torture. Simply paying $50 to boost up to 1GB made all the difference in the world. FYI--I play on a laptop, so I know your concerns about performance. I am always trying to keep my addons slim.
The point of addons is not to improve performance, but to make life easier. That being said, there are some addons that are "must-have" addons.
My recommendation on "must-have" addons are:
Autobar
Autoprofit
EquipCompare
Fubar
Fubar - BagFu
Fubar - DurabilityFu
Fubar - ExperienceFu
Fubar - MoneyFu
Fubar - QuestsFu
Igor's Mass Auction
LFG Scrubber
Metamap (and DL the Metamap Knowledge Base w/ 5000 mobs)
TipBuddy (or TinyTip)
The most resource intensive addon of the above group is Metamap, but it is also perhaps the most useful in leveling. It allows you to put notes down and search for mobs using it's database. It also provides Map coordinates, so if you look up a quest at
www.thotbott.com and a user said you could find this at 58,34 then you can 1) set a note for it, 2) put a minimap marker for it and 3) set a waypoint (arrow above your head) that leads you to it. Likewise, if you downloaded the KB, and have to kill a certain mob, then you can search for the mob and put a note on your map at the location. Very very useful.
Keep in mind, that I feel these are the best addons for LEVELING and once you start doing other things (Raids, Battlegrounds, etc) then you may have some different addons you want to use in addition to these.
Also--as you level, I would get the Skinning and Herbalism professions. You'll find a lot of herbs around as you just wander about and skinning is great because the stuff you are killing will give you skins which can be sold for money at the Auction House. In 20/20 hindsight, I would never level a character again without have those two skills while I was leveling. Once you hit 60, then you can reevaluate what you want to do. It's also a good idea to pickup First Aid (secondary) and turn a good portion of the Cloth drops into bandages while you level. Cooking/Fishing (the other secondarys) are not really necessarry while leveling and are best leveled together (catch a fish and cook it).
I'm giving the above advice because I wish someone had given it to me. The advice I got was: Don't worry about a profession yet. Ha! I later then picked Blacksmithing and it cost me a fortune and I never made a profit or anything useful while leveling. Skinning/Herbalism will keep you in the money and you will be able to afford good gear at the Auction House.
If you are looking to do some things with addons to change up the default UI, then I recommend the CT mod. You can use it to break up the bottom bar, scale action bars, turn action bars different directions, and so forth.
Linear Mode
