Does not work. Causes Steam to crash.

Loads fine but I have strange issues with video. Haven't tried any type of compatiblility modes yet assuming it is possible.

My computer configuration:
AMD X2 3000+
2GB Ram
ATI XL800
Asus MB

Steam seems to work without any issues. The game itself didn't launch on 64 bit environment, but after adding the -32bit switch to the launch (or shortcut) parameters, it started without problems (didn't test much on to the game).

This seems to be more of a native x64 issue (related or unrelated to Vista 64), that according to some forums just appeared with the recent HL2 updates.

Vista handles security (and automatic measures for virtualizing the secured locations) differently for 32 and 64 bit native applications, which may also lead to the issue being Vista related.

Regardless, the -32bit switch made the thing work at least for me.

Kallex

Runs great

Have no issues with Vista (32-bit) and Half-Life2.

I'm just curious to why people are running 64bit? There is no apparent benefit of running Vista in 64bit mode.
I found this (among others) when deciding which version to run with: http://www.geekpatrol.ca/2006/12/32-bit-vs-64-bit-vista-benchmarks

My Main System Components
Core2 Duo @ 2.4 GHz
Asus P5N-E SLI motherboard
Dual BFG Geforce 8800's in SLI
Sound Blaster Fatal1ty