Thank you for your suggestions. Those are pretty close to what I'm looking for.

After another total 4 hours of research, I think I've found the perfect headphones for my needs... or, at least, as close as I'm going to come to "perfect". Decent audio quality (lacking in bass, but I'll live); adjustable boom mic with in-line controls and a mute function enabled by locking the mic in an upright position (very neat feature, no blind fumbling when a quick mute is needed); uses only one 3.5mm jack and includes a USB extension, but reportedly works fine with a splitter. Yeah, yeah, I know, it's a first-party accessory. That doesn't bother me, and besides, it's the best thing I've found in my price range.

Before I buy, what do you think? Do you have any personal experience with these headphones? Something I should know?