I had a girlfriend years ago who insisted that cold water worked just as fine as hot water. While I didn't write down any observations, I did do several loads of laundry over the next couple weeks where I adjusted water temp as a variable, and found that things typically smelled more fresh when they were washed in hotter water.

Maybe it's placebo, maybe it's my detergent, maybe it's something else, but for me, personally, I always wash non-delicate laundry with hot water because at the very least, I feel like I smell better, and that's worth it to me! :)