I have some silk plants that are fairly 'real-ish' looking, I got mine from ebay. If you search silk plants there's quite a wide selection of types, might find something you like there.
Silk plants are much more realist than plastic, slightly dearer but look better, especially if you stick to the original shape and colour of the real plant instead of going for mad yellow or pink looking things, some good quality silk plants can look like the real thing when looking at the tank.