ok, first question: how do you want to play the pot? You can either a) try to play a small pot, with AK as a drawing hand, or b) try to play a big pot head up. You do NOT want to play a big pot multiway. So if the answer is (a), you need to just call. If your answer is (b), you need to raise big enough to make it heads up, right around 400-450 (I would say 300-350, but you have to add more for the caller). You HAVE to know why you're raising. This is what Harrington calls a "dark tunnel" raise, it doesnt really accomplish anything, and you gain no information whatsoever.

On the flop, the pot sits at 735. You need to see where you are at, so 250 is a little low. You need to be around 400-500 to get info, although I am not opposed to potting it to take it down.

On the turn, the pot is 1485. Again, this comes down to how you have been trying to play the pot. Right now, you've bet all the way, and gotten called (not raised). The bets havent been big enough to find out enough concrete info. AND, if someone was on a flush draw, they hit it. IF you did not have a the Ace of spades, I would bet 1/2 pot, and fold to reraise. However, since we have the nut flush draw, checking and calling is fine here, specifically because we do NOT want a reraise if we raise. If we are behind, we have redraws, and we may very well have the best hand. The last thing we need here is to raise, get reraised all in, and have to fold (or make a real hard decision). Check/call here because of the draws.

River has the same problem as the turn, we're either way ahead or way behind. If we bet, and get reraised, we're stuck. Check/call is good here, keeps the damage small if we're behind (we have to call something reasonable here), but also increases out chance of picking off a bet from Ax or Kx (or a bluff? pp?).

Just remember, you have to know WHY you're raising, not just that you SHOULD raise. AK is a hand that, depending on the table and position, I will either flat call or reraise big, but it cant be in the middle. You only get the worst from each side. Just my 2 cents. -=J=-