I'd like to buy some games for someone as a Xmas present, and I'd prefer that they were from GOG, but I want *them* to choose them to ensure they get something they (a) actually want, and (b) haven't already played. As such, having me choose the games isn't really a viable option. I want to do the actual purchasing in advance, however.

Is this possible? The gift system seems to rely upon me choosing the games.

I realise there are issues if the final cost does not match up to the cost of the voucher (e.g. a $10 voucher used to buy a $6 game leaving a usually-useless $4 left over), and GOG undoubtedly has no ability to remember and track store credit, but I'm hoping there's a solution. I'd be perfectly happy with "the recipient can choose games up to the value of the voucher, and GOG keeps whatever is left over."

If no such system exists, is there a workaround whereby the recipient can email GOG support staff with the (unused) gift codes, and request that they be re-assigned to the games of their choice? If so, what sort of response time should I tell them to expect from the support team?

Those codes do exist as I think those are the kind that are often offered as prize for the contents. However putting on sale might indeed be tricky point.

Well that is impossible at the moment, but I thik gog.com is preparing similar service. Please note, that with Witcher 2 EU customer will receive $16 credit to spare on ANY game on gog. So I assume that soon we will have some kind of "money accounts" linked to our personal accounts. And that opens new possibilities...such as gift vouchers, discount vouchers (pay $50 in real cash and receive $60 on gog.com), credit line (buy now - pay later) etc.

Yeah, I think for now you're going to have to go with good old fashioned printed vouchers from you saying that you will buy them x number of games totaling a value of $10 or whatever. And then just have them tell you what they want and them gift them afterward.