I personally have never really noticed vertical tearing. It's only really prominent if something is strobing rapidly (like muzzle flashes), and I just don't think it's worth wasting extra CPU cycles to enable VSync modes in whatever game I'm playing.
I'd like to add that Deus Ex is my alltime favorite game! Just perfect in every way. Never played the PS2 version though, could somebody somehow share this orchestral theme song?
Also, the timesplitters serier is RAD! I love them all! You need all three of them, as Timesplitters 1 is the speediest, most challenging, and most retro/harcore out of them. Timesplitters 2 has flametag and missions that are different based on difficulty. Timesplitters 3 has lots of playable characters, story, modes, vehicles, but sadly, is WAY too easy.