The best ones are the ones with a cup arrangement to put bait in, this way they have to stay there and eat the food instead of pulling it off and legging it to eat elsewhere. Ive had good results with peanut butter, but the best ive found is that cheap chocolate spread you can get for sandwiches.
I use the T Rex traps from ratbait.co.uk as these are what the pro's use in the retail outlets i fix fridges in. The added benefit it that you can set them with your foot.
