Swords are a good example of a plant that won't get eaten by dwarfs. Neither will java fern. This is the case with most fish in fact - these plants tend to be left alone.
Having said that, you can always get round the issue simply by getting one of the many extremely fast-growing plants available for aquariums. I, for example, have discovered h. polysperma. I am serious when I say that this literally grows half an inch over night - no extra lighting, no fertilizers, no CO2. That way, you don't need to worry about the plants being destroyed anyway.
Using lots of floating plants is a good idea as, a lot of the time, the only reason gouramies will cut up plants is to support their nests. Note that this doesn't necessarily mean they'll build a nest as it's unlikely that the conditions will be perfect for spawning (eg: too strong a current will prevent a bubblenest being built) but this doesn't stop them from cutting up leaves in preperation. Many floating plants also have the advantage of not being particularly edible as they tend to have broad, often quite tough, leaves (eg: various lilies).
Again, most gouramies aren't normaly a threat to plants so, if they are cutting yours up, it's probably a sign that their diet isn't ideal (if they are eating the plants that is) or it's all simply linked to breeding behaviour and can easily be stopped by adding more taller (or faster growing) plants or floating plants.
. They are lovely though.
mind you i did find that they stoped eating them as qick after i put the fake plants in i think they tryed eating fake plant and found it not tasty 
but they still destroy my plants 
any way that all i no i think i will watch the other replys to see if any one has any good answers to this problem as well .....oh most of mine are three spot gouramis just incase u wanted to no
