Mine is Roy, originally from Fire Emblem (Gameboy Advance) and featured in Super Smash Bros Melee (Nintendo GameCube). While I'm not a super-huge nerd for either of the games (yes, I enjoy them both, but not as much as my avatar may imply), it's been an avatar I've used for a while.

When I was playing Smash Bros Melee with a close friend of mine, we happened to unlock Marth and Roy. Being gaming rivals, we each picked one to represent us, and often have Marth vs Roy duals. To stay sharp enough to bring on the pain, I played Roy as often as I could, and ended up really liking his style (even though he's often regarded as not being all that great -- or so I hear).

Fast forward to a college-level drawing class. We needed to draw a bust of a person or character, and were tasked to pick something out. I took a photo of my television screen (of all the ways to get a screenshot), and used that as my subject. Needing an avatar for Icrontic.com, I re-sized it and have been using it everywhere ever since.

And that is my story of using Roy as my avatar. Hope you enjoyed it.  

I've had that issue in the past, and here's what I've gathered. This is not proven 100%, but may give you a slight edge to preventing it.

I've heard that the autosave fail is triggered by pressing "Y" (replay the level) too quickly after completing a level (touching Bandage Girl). It probably interrupts the auto-save that normally happens when you touch Bandage Girl, thus glitching it up. It's usually avoided by just watching some of the replay, just a second or two so the autosave is guaranteed done.

Generally, I've found that you can verify that autosave is working correctly in two ways. If the little "autosaving bandage girl" icon is appearing in the bottom-right when you beat a level, things are probably fine.

But if you want to be fully sure, go try playing a level with a bandage you haven't gotten yet. Get the bandage and complete the level. If the bandage appears on the map screen on the level you just beat, things are fine. If it doesn't then the glitch has occured. Yeah, it sucks, but just exit back to the Xbox dashboard and re-launch Meat Boy and re-do what you missed.

As long as you're constantly aware of if you're autosaving and keeping the bandages, you should be fine and not miss too much if the glitch occurs.

Hope this helps!