I'm not sure it's a forbidden fruit, but...
I wish I had the money to pay the debts off from two years ago once and for all after I was taken to the cleaners financially by someone I made a HUGE mistake in trusting.
Reason 1: It'll finally bring closure to that whole episode
Reason 2: It'll get the banks to leave me the hell alone
Reason 3: It might finally give me a clean credit rating for the future.

I wouldn't say it's a greed thing, I've been craving closure to this episode for the last two years and I seem no closer now than I did then.

Now as far as desiring things I want but can't have, sure, techie gear all the time. Home entertainment center, couple more computers....

I've also had problems since 1993 about being addicted to online chats (not continually, it comes and goes)....
But I know even today there are things I SHOULD do that I don't do or put off doing....
Ironically, networks and computer systems are one of the things I excel in (upgraded the software on a former co-workers laptop over a span of 90 minutes yesterday, voluntarily - and achieved her main goal as well, getting her HP inkjet printer working under Jaguar).

Probably more info than you wanted, Lilith. :P