At first I was against the idea, I thought it takes a lot of the whimsy out of the system if you have even a reasonable chance of "finding" a magic item you were hoping for. But with the glut of magic items now available, far in excess of what was in prevoius editions, you practically have to if you want to get anything that is a good fit for your PC.
Then I was DM, and I found myself hoping for a wish list form my players. It became next to impossible to provide meaningful items for the PCs unless I was totaly versed on all the classes and builds and what they really wanted. Sure you can throw a decent set of armor, but even that is tough as there are a lot of armors out there tailored for certain builds. I came to find the wishlist very helpful.
Over on the 4e board, someone mentioned how much they hated the magic item wishlist.
Now maybe it's just me, but I've been using magic item wish list for characters since 1st edition. Talk to the players, see what they want out of the system, find ways to incorporate it into the game. I'm not so smart that everything I think of should go into an adventure and hope that it's useful to the players.
Other people's opinions?
Nay.
In general, my feeling is that if your PC really wants one specific item, you should do something to find it in-game. Announce that you're making inquiries about such an item, talking to sages and rumormongers, digging through musty tomes, whatever. Unless the item is one that I just flat-out don't allow (in which case I'll tell you up front), I'll give you some clues and opportunities to follow up, and if you do follow up you'll eventually find whatever it is you're after. Then you'll have the satisfaction of having earned your awesome item and I'll have some more adventure hooks.
Or, if you don't want to go through all that, get some money and ritual components together, buy the party wizard a copy of Enchant Item, and have her make it for you.
I'm not much into power play, and magic shops and wish lists are much unheard of in games I've been part of, on any side of the screen. With one player though, he invested so much time and thought into his character build, that I knew that providing him what he wanted would give him more gratification than the unknown. There was a heavy toll attached to it though, and he roleplayed his ass off to get what he wanted. It was no Pun-pun or a cart-worth of nightsticks thing, it was as much part of the player as the backstory, more so maybe.
So if it's justified, I'm happy to oblige a wish. I try to avoid it as much as possible though, as I prefer even some wastefulness to hyper optimization. I feel that it narrows the sweet-spot a lot.
I guess I like the magic item wishlist because it allows me as the GM to determine when its going to get into the game. In your example, it sounds like the character knows more about what the magic item is as opposed to the player which, may sound funny, to me me reeks of meta-gaming.
*blink*
Metagaming?
Where's the metagaming? I assume PCs have some knowledge of the game world, enough to have heard of such a thing as, say, a flame tongue sword. The PC thinks that would be an awesome weapon to have and sets out to find one. No metagame knowledge involved.