Left hand offset snips are made to cut straight and cut curves to the left. Rights cut straight and cut curves to the right.
Snips marked as straight cut are only good for making short cuts from an edge, like cutting a notch in sheet metal.
I've owned about every major brand of offset snips on the market, and my favorite brand is Midwest. http://www.midwestsnips.com/products...id=45&cat_id=1
A lot of the snips on the market with other names are made by Midwest with private branding. At one time Snap On was selling Midwest, but don't know if thats still the case or not.
The pic Brian posted is of a Proto branded snip, but I'm pretty sure its actually made by Midwest based on overall appearance.
Wiss offset snips are decent, but not as good as Midwest IMO. The Wiss offsets are shorter and more stubby, and just don't feel as good in use.
Klenk is another big brand of snips, but I've never run into anyone who likes their offsets. I had one set of them, given to me in near new condition by a buddy who said he hated them. Later, I gave 'em away too
Don't know if they're still made or not, but Wiss used to make a pair of snips that cut out a narrow strip of metal by using 2 upper blades with a lower blade between the two uppers. They're really handy in some applications because they'll cut with the least distortion of any type snip.