i eat hummus in sandwiches all the time. you can also use it to dip vegetables. there are a lot of bean dip recipes all over the net, too.
for another dip, i use a vegan cream cheese mixed with salsa. it tastes just like it has real cream cheese to me.
if you really like mayonaise, do you know about nayonaise and other vegan brands of fake mayo? i only know about it because i like potato salad. these vegan products must be pretty good because i cant choke anything down that isn't tasty.

also, instead of butter, i pour a little cold olive oil on vegetables.