I've been playing Arena in my free time (not very often) to ease any desire for Oblivion. It works pretty well because you can visit both Cyrodiil and Morrowind, and it's always interesting to go back and see the original (like seeing the volcano in the background in Morrowind). Not to mention its like getting a new Elder Scrolls game by just playing it.
If you decide to play, left click + sideways movement of the mouse makes you swing a weapon. Also, be sure to follow the installation instructions, and Ctrl+F12 makes the game run much, much faster.
