My next great multi-purpose mic (mainly vocals)?

[Jack Q]

Hey everyone,
I'm looking for a new mic to add to my collection, but can't completely decide what I should invest in. I've researched quite a bit.
At this point, I have a Shure SM57, an Audio Technica AT4050 condenser mic, and a Sennheiser E835 (mainly to be used for live vocals similar to the Shure SM58).
I record in an untreated room and I'm looking for a good, all purpose mic. My main goal is to find a mic that will get me better recorded vocals.
I have narrowed my search down to the Shure SM7B, as I have read many great things about how it is good for recording vocals, and also a good mic to use in untreated rooms. I've also read its good for recording a variety of different instruments.
I was wondering if anyone else might have any other suggestions on what would be the next best mic for me based on my needs AND the mics I already have. At this point I don't want to spend more than $400, unless someone can make a really great case for something amazing.
Thanks!

[MASSIVE Mastering]

I think you're already on the right track.

[elperuano]

The SM7B is good for the reasons you mention. I own one and don't plan on getting rid of it (ever). Use it as my primary vocal mic, ESP in unideal spaces. Ive also used it on kick and found it to be very capable for the job.