I am a CS:GO man now. Reluctantly. It is the most neutered version of all time I admit.
BUT
it is great for competitive online tournaments!
5v5 matches
current anti-cheat technology
Everything about this latest version "Global Offensive" is all about competitive play, over friendly matches and customization.

However you do make a great point!!!
because:
CS 1.5 is the greatest version of all time, and always will be.
plus IT IS FREE!!
And to the best of my knowledge Valve does not hold half as much ownership over that version, as they do over any version post 1.6


The biggest issue with 1.5 however, is how excessively exploited it is.   I am not sure that I would wager any money on 1.5, unless it was a private LAN match.


CS:GO is only $15, so if you are any good at it, you can win your money back yeah I said it
Counter-Strike: Global Offensive
http://store.steampowered.com/app/730/
or
https://steambitshop.com/?page=item&id=57