Well I think that any blender would do.
Look for one that has at least a 400watt motor or higher and one that crushes ice. After all your only going to use it to mix your protein shakes. with the oatmeal the best thing to do is cook it first, let it cool off, then put it in your protein shake.
Hope that helps.
Walmart has some good ones …
i use the pro braun stick blender. it makes my pwo drink more milk shake like and it can handle ice. it is easy to clean and the fold design of the blade enclsure prevents the shake from splashing out of the cup.
I am on my 2nd one of these. The first one was used on average daily from 1997 through early 2003 until my sister killed it by shorting out half the shit in my kitchen. Check out the online feedback. Durable as hell.
Here it is for $79 after the rebate (note no taxes and free shipping)!