how about a hallmark card?
cheap, but shows that you remember the occassion. I've had my wife beat me over the head when I failed to acknowledge an important date with a card or some flowers. We celebrated our anniversary this week and I got her the card and some flowers...these things mean a lot to the ladies, fru fru or not. Shows 'em you're a sensitive and caring man.
Now all the other stuff like jewels and nice vacations is so that she doesn't ask how much you spend on your car