Depends on your goals.
The 737 sim may not be glass, but the type rating applies to the NG. You just need differences training. If you want to go after Southwest employment go this route. The 737 is still one of the most popular planes in the sky, but with the exception of Southwest not a lot of jobs out there for this one.
The A 320 is the other real popular rating to get. You will be learning fly by wire control laws and a really effed up FMS system so it is a tad busier of a training evolution, but if you want overseas work this will go far.
As mundo1 said, 500 in type is just about required for any expat jobs and 500 PIC is required for any direct entry Captain jobs.
Also, the A310 is a separate rating from the A320 and not very popular as there are few 310s flying these days. OTOH, the A320 is good for the 318, 319, 320 and 321. With the 320 on your ticket, the 330 /340 is a short course as well, so it's a good one to get.
If you are looking for the big iron jobs, the 767 or 747 ratings are good, if you again have the 500 in type or get on with one of the MIA freight companies.
Good luck!