Last year I bought two Radeon HD 4860's. They came together, but did not come with a Crossfire bridge. With Skyrim announced I finally decided to stop being lazy and spend a whole 10 buck to get one lol.
If you already have the cards, that's one thing, but I really don't understand the point of buying two cards when you could buy one card for double the price and have it perform as well or better than the two on their own. I mean, there's a card for any pricepoint these days and for the most part the price is directly proportional to performance, so why would you bother with two half-way-there cards and hook them up with some silly flimsy dongle when you can buy one and have it be the real deal.
Ok, yeah, so i see that if you chain three top 'o the line cards together you could theoretically get this uber amazing system, but there isn't a game on the market that can't be played with a single high end video card. And if you're trying to future proof your system, it would be far more prudent to simply update to the latest and greatest every 9 or 12 months than to blow all your money at once on some delicate multi-card setup that might not be as effective after a year and a half as something brand new down the road.