I prefer "If I were a rich man" to "If I was a rich man", though apparently I am in the minority. This despite the fact that someone who is as bad at proof-reading and litters his posts with grammatical and spelling mistakes cannot afford to be snooty about verb tense.
I vividly remember the year in Spanish when subjunctive verbs were introduced. After slogging for years learning verb conjugation on all kinds of tenses, it came as a rude shock that there was an entire second set of parallel subjunctive verb conjugations. Eeek. It was like completing your tool box after years of careful purchases, only to discover you needed a second set in metric.
I have forgotten most all the Spanish, but since then I remain fascinated by what, to my knowledge, is the only remaining subjunctive verb conjugation in routinely-used English.