I love the smell of a darkroom. With that said, I handle enough chemical nasties in my day job that "aged" fixer smells downright pleasant . Not too long ago, I needed a low BP solvent for gas chromatography work(ended up going the opposite route to do what was I was trying with DMF, a very high boiling solvent, but I digress). I ended up working a lot with carbon disulfide(CS2)-I use to use a liter or two a week of the stuff when I was working in a fuel lab. It's NASTY smelling stuff...and even worse if you accidentally catch it on fire(don't ask how I know that one). I also tried tetramethylsilane(TMS), but it's too expensive, and couldn't find a fluorcarbon or CFC that we had in stock with a low enough BP for my purposes but high enough to handle at room temperatures. Fixer does give off some nice sulfur compounds that stink, especially when it sits out in a tray. Rapid fixers, with their combination of ammonia and sulfur compounds, are even worse than plain hypo.