I'd get the MEI and call it good. If you desperately feel like spending cash, buy the twin piston time. Until you know you want to fly for an operator like Southwest a 737 isn't going to help. Personally, I thought I wanted to fly for Southwest until I flew freight for a couple years... now I have no desire. I had considered a 737 type years ago and not getting it was a good decision on my part, it would not have helped me yet and I don't forsee it helping in the future (never know though, i may change my mind and apply years down the road and get the 73 type).
The only type that i would consider paying for at the moment would be something like a Ford trimotor. Something fun, something that may be a good interview conversation topic, and something rare. Will I get it? Doubt it. That's still a lot of cash for something I won't ever use. But of all types, that's the one that stands out that I'd like someday.