I probably once worked for the 767 operator you have an offer from. Be prepared for poor maintenance and substandard hotels. From my perspective of 25+ years in this industry, this decision is a no-brainer. The A320 option is the obvious choice, both for short term and long term opportunities.
Since you are new to the industry, multiple short sectors per day is a good thing rather than a bad thing. You need the practice of many approaches and landings. You'll be down low in the weather more, and you'll be making more decisions. It will make you a better pilot.
The 767s are getting old. It won't be long and the charter and freight companies will be the only ones operating them. It is an easy transition to the 777, but there seem to be few companies offering to accept 777 pilots without significant time in type (Korean Air is the only one that comes to mind).
A320s are one of the most popular airplanes in the world and are still in production. Airbus can't build them fast enough. There are lots of operators (especially China) who are offering top $$ for A320 people due to shortage of qualified pilots. The transition to wide body Airbus aircraft is equally easy as within the Boeing family.
Good luck with your career.
GoForIt
Last edited by GoForIt; 7th Apr 2013 at 00:10.