Just because its a lot of addons, doesn't mean he/she uses them all at once or for all characters. I used to have over 160 addon folders (some mods have multiple folders)
. I have since shrank that number to 110 as of last night. I usually hovered around 60-70 mb. Now w/ 110 addons I have that memory usage down to about 35-40.
Ace mods helped me, but I like the way they work, not everyone does.
Out of the addons you mentioned, the Auctioneer pack and Metamap were the biggest memory hogs for me. Dropping those helped tremendously. As for alternatives, thats a hard one without knowing what you use some addons for. I switched to Cartographer from Metamap. Getting rid of Gatherer (big memory hog) hurt a lot, but Cartographer has its own plugin.
Just to let you know, Data Mining addons take the most memory.
I use a couple of addons to match Auctioneer's feature set, including 'Fence' and a few others. I have converted mostly over to Ace Based mods, which have helped greatly. I also switched to Fubar from Titan. Great addon imo, but ymmv. Post back if you have any questions or comments.