Yeah I must admit I hit that stage several times.

What I started to do was I organize a Pre-Bc and BC raiding team made a post on the forums, advertised a bit in LFG etc. Made our own channel called "OldRaids". Soon there were people joining it nonstop.
We basically cleared every instance out there. ZG,AQ20,MC,BWL,AQ40,Onyxia,Kara,MAg,Gruul,SSC,TK,H yjal,BT and a bit of SWP.
This I found alot of enjoyment from and started to do it weekly, started collecting all the different tier sets. I'm even working on Sulfuras , Hand of Ragnaros on my paladin (Level 60 legendary). I just need the eye of sulfuras then its mine!

Anyways the other day some friends and my self decided to step it up a notch. We all rerolled alts (or joined on already bade alts) and are leveling to 55. Once at 55 we will take turns running those alt through places like Zg, MC, AQ40 etc for gear.
Level 55 alows us to be able to gain xp from killing bosses without leveling us above 60. Also being in a raid group cuts xp gained by alot.
After that we will get some pvp gear and do AV etc together - enjoying the life of pre-bc again.

This is really taken off well, we have about 25 people now and we are all eager to hit 55-60. Our first raid is this weekend

Anyways this is on Stormrage Alliance (US) if anyone wishes to join me. - Can wisper Ruinic of Nhanced.

Peace.