I personally hate RealOne / RealPlayer 10 too, for
1) They are becoming too bulky as compare to what I want - a simple video player for RM/RMVB formats;
2) They contain spyware-like components that I do not feel ease with.
You may check out something called RealAlternative. RealAlternative comes with a set of RM/RMVB codecs as well as a player "Media Player Classic" (this is different from Windows Media Player, although its look is similar to the old Media Player in Win98). However, I usually prefer installing only the codec part of RealAlternative, while using the latest version of Media Player Classic (MPC) directly.
All the above software can be found easily in Google. They are freeware.