Most players can play any DVD - if the DVD is purchased in the US, it's most likely Region 1 and will play on your player. If you get a "Region 0" or "Region all" player, it'll play all regions. Still, it doesn't matter what you get!
I would recommend holding off on getting a Blu-Ray DVD player. At the moment Blu-Ray is still coming out with new features and the current models of Blu-Ray DVD players are not upgradable. Upcoming features will be in the profile update version 2.0 which adds more memory (from 256MB in Profile 1.1 to 1 gigabyte) to a player and requires Internet connectivity via an Ethernet port. BD-Live also translates to online content, such as games and movie merchandise shopping.
Both Bonus View and BD-Live players will be available to consumers by fall possibly in October 2008
Sony has stated that only upgradable Blu-Ray dvd player that will be upgradable to Profile 2.0 that is on the market is the Playstation 3 otherwise consumers are urge to wait until better Blu-Ray DVD players are available.