Crypts are fantastic aquatic plants and tend to cause little problems to the hobbyist. They are very adaptable to a wide range of water conditions and the species is very broad too.
One of our favourite crypts is crypt bullosa which is a greeny brown plant with slightly dimpled leaves. This makes it look a little different in your aqaurium and one of the reasons it's so attractive!
This particular plant looks delightful when planted in groups of 2 or 3 and looks even nicer if you plant it around rocks (something like mini landscape). This provides immediate impact and is very easy on the eye.