The tech industry has an unmatched propensity for causing buyer's remorse. Gadgets are meticulously engineered so they appeal to both the hedonist and the utilitarian, while annual refreshes ensure that you're always one step behind the curve. It's a formula that generally works well enough: you're regularly supplied with new toys and companies get to report record earnings.
However, it's only a matter of time before even the most prudent shopper gets burned -- be it their own fault or not. Whether you invested in tech that didn't pan out (like HD-DVD), built a new computer weeks before a major generational shift, splurged on a "luxury" item or have an unboxed iPad 2 in your closet, we're sure all of you have at least one tech purchase you wish you never made.
Besides preordering the occasional dud (Dragon Age II most recently), I think the Thermaltake Tai-Chi is my most regretted purchase. Although it's served me well over the last seven years, it doesn't have any of the trappings you'd expect from a modern enthusiast chassis. Yet, because it cost about $450, I feel guilty replacing it. I probably would've been better off with a $100-$200 case.