PS3.
60gb at launch, with two games and two sixaxis controllers: about 800 euros (1,000+ usd). I have two reasons for my regret:
1) A waste of money for a faulty console
Local Sony servicing denied to repair it in warranty: "We and Sony can't shoot ourself in the foot admitting your PS3 is faulty!" screamed the service owner to me over the phone when I insisted it had a faulty blue diode and it had to be repaired in warranty.
I fixed it with a refurbed optic group I bought via ebay (about 80 usd more, the local Sony service asked for about 350-400 usd to fix and ship it) but it lasted three months before breaking again. Had to buy another PS3 later (400 euros / 500+ usd more).
2) Expected a PlayStation lineup
First two PlayStations lineup was made mostly of thousands of exclusive japan games, with a few multi platform games both western and eastern, and got great new IPs, great sequels, tons of good games, huge variety and many new ideas implemented in gaming.
The PS3 library is mostly made of multi platform western games, while exclusive Japanese gaming has become a ridiculously tiny niche, with a lot of IPs and genres killed or severely mutilated. I occasionally setup the PS3 just to play online beat'em ups (ie SFIII ts) with a couple of friends or to play one of the few SP games I like (ie Yakuza IP).