I LOVE soloing old world content for transmog sets, and it's amazing how much gold you can actually round up from all the greens! A single run of Black Temple netted me over 380g for about 45 minutes of fights.
There are a few tricky fights out there however, even at 90 and with 408 hp, some fights still prove to be difficult.
Here is part one of my series I will be putting together, featuring the Illidari Council, from Black Temple.
Pop you're CD's and stick to one mob, and everything will be fine!
(Don't pick the healer, she has a reflective bubble and becomes immune to damage every now and thing!)
There is now a portal to help transport you once you down a few mobs, so there is no longer a 45 minute run back to Illidan!