One thing I love about crewel embroidery is the solid colour you can create with the thread in imaginative ways that bring out texture and shapes and movement. I've found some examples from the flickr embroidery pool showing what I mean.
This close up of a circus embroidery from Merwing is absolutely gorgeous. I love the colours she has chosen for this work.
Misslilamae's freeform embroidery is great too. Her experimentation with the stitches in summery colours looks a little like a funny fish or face ala Picasso (If he had ever embroidered).
Robot from Beetastic. She's also just embroidered a really cool tea towel.
Tiggywinkle started this amazing bird, but apparently got tired of all the orange. Hopefully she'll feel inspired to finish it one day.