i've had to many random bugs with 7, particularly with WiFi (full propper legal installs) on various machines. But still had a lot of problems, it refusing point blank to work, mother T's laptop after an update screwed the WiFi too.
XP or Mac OSX here, I avoid 7 at all costs....
The only time I've had any real issues with Win 7 has either been because of flaky hardware or poor driver support.
The other half's laptop randomly crashes the official Toshiba provided video driver (ATI), yet it will work quite happily all day long on the MS signed drivers.
Same goes for my current laptop (Toshiba Satellite R630-155). The only drivers available are for Win 7 64bit, and the Wi-Fi card (Broadcom Wireless N) cannot connect at any more than 72Mbps no matter what.
It's a known documented problem, but is only caused by poor drivers so MS can hardly be expected to shoulder the blame for that.
I'm currently customising my Win 7 install DVD.
So far I have all updates and SP1 integrated, all system drivers slipstreamed in, most of what I consider to be useless has been removed (eg, Games, DVD Maker, Media Player, etc), various registry tweaks applied (eg, add "God Mode" to the context menu).
I was up till gone 3am this morning playing with it bit by bit and running it up on a VM, and I'm probably going to waste the rest of today tweaking it some more (probably until I break it and have to start over
).