MySQL vs PostgreSQL? Which should I choose for my Django project?

For whatever it's worth the the creators of Django recommend PostgreSQL.

If you're not tied to any legacy system and have the freedom to choose a database back-end, we recommend PostgreSQL, which achives a fine balance between cost, features, speed and stability. (The Definitive Guide to Django, p. 15)

large database with several hundred thousand entries,

This is not large database, it's very small one.

I'd choose PostgreSQL, because it has a lot more features. Most significant it this case: in PostgreSQL you can use Python as procedural language.

Go with whichever you're more familiar with. MySQL vs PostgreSQL is an endless war. Both of them are excellent database engines and both are being used by major sites. It really doesn't matter in practice.

As someone who recently switched a project from MySQL to Postgresql I don't regret the switch.

The main difference, from a Django point of view, is more rigorous constraint checking in Postgresql, which is a good thing, and also it's a bit more tedious to do manual schema changes (aka migrations).

There are probably 6 or so Django database migration applications out there and at least one doesn't support Postgresql. I don't consider this a disadvantage though because you can use one of the others or do them manually (which is what I prefer atm).

Full text search might be better supported for MySQL. MySQL has built-in full text search supported from within Django but it's pretty useless (no word stemming, phrase searching, etc.). I've used django-sphinx as a better option for full text searching in MySQL.

Full text searching is built-in with Postgresql 8.3 (earlier versions need TSearch module). Here's a good instructional blog post: Full-text searching in Django with PostgreSQL and tsearch2