I've got a stick blender. Phillips 600w got it in argos about £17 it's dead powerful and comes with measuring jug so you can mix your shakes in it too.
I use a cheapo stick blender £5 from Asda, also a jug blender for crushin ice in my shakes. Both work really well! (Mind you, I do fancy the smootihe maker idea)
I use the blender I used to make my 2 kids baby food in! its like a liquidiser and does ice also. Have also got a smoothie maker, but cant be bothered to keep washing it all up 3 times a day! LOL !