Best shutoff valves?

[jkatz419]

I've had a run of shutoff valves that used to be ok but now leak gas (if you touch them you can hear gas venting). I'm looking to replace them and would rather spend a few extra bucks to get quality replacements that won't leak then cheaper ones that might. I've killed 3 tanks of CO2 in the last 2 months :|

Thanks in advance!

 

[jkatz419]

Well after getting no replies I went ahead and bought 2 of these: http://www.midwestsupplies.com/threaded-shutoff-valve.html
Mostly because I was ordering some other stuff from MWS, hopefully they aren't garbage quality (the reviews with several different end attachments were all pretty positive).