Recently I was playing a bit of Oblivion, and I noticed the ridiculous number of keys I had. I thought to myself, "Ooh, I should clear these up. I surely can't need all of these keys..."
And you know what? I was right... but I didn't know which keys I needed and which I did not.
Now, admittedly, keys are zero-weight. This means they are not a burden on gameplay. But It also means I have to cycle past all of them if I want to access my soul gems, or any sort of stone, or miscellaneous item, or torch, or repair hammer. And so on. When you've been playing for a while and have dozens of keys, this can take about ten seconds at least and gets rather annoying.
My suggestion: give the player a "keyring". Not an actual keyring, mind -- just some section in the menu where we can look at our keys independently. It could even be a bag or something. Just have it so that the player can scroll right past it if he wants to; when you want to look at your keys, you just select the bag and open it.
Besides, who wants to look at keys?