As of May 1, 2008, the United Nations has 192 official members (including Montenegro and Serbia - the two newest nations). That number does not include the Vatican, and it doesn't (yet) include Kosovo.
How many countries have you visited?
( England, Scotland, NI and Wales are not officially recognised countries, The UK is the official country. You can add refuelling stops in the middle east, even though you don't pass their border controls and get a stamp, so you aren't technically in the country.)
Although I've travelled a lot, I haven't actually been to that many countries, as I have a tendency to keep going back to the same countries and keep exploring in the until I get bored. Consequently I've been to The Netherlands 20+ times, and Greece, Spain, France more than a dozen times each.
I'm guessing that Terpe, Ricky, Tawi, AlanmF1 and Subseastu are are most widely travelled members
Where have I been?
Europe:
UK
Rep of Ireland
Belgium
France
Spain
Portugal
Italy
Greece
Austria
The Netherlands
Denmark
Germany
North America
USA
The Bahamas
Oceania
Australia
Asia
Bahrain
UAE
Qatar
Oman
India
Turkey
Singapore
Malaysia
Thailand
Brunei
Vietnam
Philippines
Hong Kong
Macau
29 in total, so there's still a lot more of the world to see