Just saw that there's a "7 databases in 7 weeks" to be released. Kind of like the 7 languages except for DBs...just moved onto my must get list, probably a good overview since my DB knowledge and approach is pretty much
1) RDBMS...if in doubt use postgres because it has tons of features, runs on all OS I'd ever want to use and is Open Source. If forced to use MSSQL or Oracle..curse (at SAP). Also avoiding MySQL ever since Oracle got involved.
2) noSQL...buzzword alarm bells go off, turns out I did noSQL for a living without relizing it though i.e. ZODB..object databases are nifty and nice (but should probably be indexed by using a RDBMS anyways) would like to use them more but RDBMS+ORM is good enough for me
3) Random other DBs...no clue
Basically I'm just a DB user (from code) that doesn't worry too much about DB details, my design is done DB agnostic and I usually just hope it somehow works