With guild perks and achievements my opinion towards guilds and my alts has changed drastically. All of my characters, even Faid, were in my own personal bank <Champion> for most of Wrath. It was just easier to have them all, effectively, have a shared inventory. Need that Fire to Transmute a Cardinal Ruby? It's cool, go to the bank. Oh, you meant Titansteel? To the bank! No need for toon swapping!
Then Cataclysm came and Faid moved to <Legacy of the Illuminati.> I love it there! It's really put a crimp in my banking situation though. For the first few weeks all of my alts remained in Champion, and other than any time Faid needed to smelt something for others, the banking was still pretty smooth.
Then I began crafting, leveling, etc. Guild perks were too tasty to pass up. One by one my alts have left Champion and joined LotI. The last holdout, my JC/Tailor Klix, came over last night. This has seriously changed the way I bank, craft, and generally deal with my alts and their professions.
Remember Rebellious? Not so cow-like now! With Verixi handling things just fine on Horde and a need for a toon to hold Champion for me, I rerolled Rebellious as human. Dirty dirty human hunter.
I played around with a few ideas. My first idea was to have Rebellious be my "AH Toon." This was largely how I did things in Wrath; all items were purchased by one character and placed into the guild bank. I would go to each toon separately, craft whatever they were to be crafting, put it back in the guild bank, then I'd go back to the buying toon and sell everything. I thought about doing this same thing, but through the mail. That wasn't going to cut it, though. I knew it was inevitable that I'd screw it up: mailing things to the wrong toon, forgetting to mail that one thing I needed, etc. etc. I would just get a headache pretty quick.
So I've decided to do this: Other than volatiles, most items I have are used by only one character. My tailor is the only one who really needs Embersilk and gems, my Blacksmith the only one who needs bars, etc. So I've basically dispersed all of the items from my guild bank into the appropriate character's personal bank.
What's this left me with, though, is a rather barren guild bank. Back when Champion was nearly full of tradegoods I had made other banks for other uses; All the Things to hold my vendor recipes to sell, Your Self Storage to hold my stockpiles of older stuff I needed to sit on for a while so they could grow in value. But now, I've got so much space among the three banks! (Champion: 6 Tabs, All The Things: 5 Tabs, Your Self Storage: 5 Tabs)
I'm considering moving everything from my stockpile bank to Champion and selling off my stockpile's guild bank. The other question this brings up is gold. I used to use Champion as a sort of savings account; each toon had a certain amount of gold they had with them at all times, between 100g to 5000g depending on the character. Any excess was placed into the guild bank; it was nice since it kept me from making silly impulse buys! =D But now, with each toon unable to access the guild bank, I'm playing with the idea of a "payday." All the money will still funnel into Champion, but basically every toon will have their own starter cash per week. I use that to buy their own specific items, craft, and they sell their own items. At the end of the week, they send everything but their starter cash back to the bank. One perk of doing it like this would be I can have a very visible sign of what toons/professions make the most gold for me.
How do you handle your banking/crafting setup on multiple alts?