I would suggest reading about Bitcoin for 3-4 days (in your spare time obviously) at least, before making a decision.

It's more profitable to buy Bitcoins if you are betting on the exchange rate going up.

It's less risky to build a mining rig if you are betting on the exchange rate going up. (You have the hardware to sell if Bitcoins are worth 0 in the future)

The cheapest mining rig that can achieve the fastest hash rate is the best. This is usually one that you build yourself. If you already have a computer with pcie slots, it's possible to add a new video card (AMD) and mine with your existing hardware.

Again, I suggest you read, read, and read some more before you make any decisions.

Um, no, it's the exact opposite.  If you bought a mining rig 2/4/6 months ago, you would have less bitcoin-value than if you had simply bought bitcoins on the open market.

My mining rig only cost me $480 with a 6870 and 5770. I will recoup my costs in less than 6 months. It is still profitable.

but what would $480 of bitcoins bought when you bought your rig be worth today?
how many more btc would you own today if you had bought btc instead of mined? and current value of that 'btc gap' ?
add electricity costs and subtract current value of the equipment to determine if you're in the red or black.

no one's saying that you can't make a profit - just that the more the price goes up, you more you have lost 'potential revenue'.
it's as if you are betting that price won't increase much if you buy gear instead of btc in the market.

the good side is that if the btc are worthless tomorrow, you still own a computer and only lost some of its value.

great thats good! Sorry I didn't want to offend you. It's people like you that got the market started and help with demand. I also don't get any btc handouts every day, so I just have to wait idly by and hope my investments pay off.

we are all tied to btc success no matter how we got in to it.