Yes , Low, Heroes and (strangely) Lodger are regarded as the best of Bowie. I have all three, but Philip Glass hasn't, as yet, written a "Lodger Symphony"!
yes 'the Berlin Trilogy'. I like pretty much everything bowie did in the 70's (even lodger had it's moments).
Got to meet Phillip Glass in the early 80's, here's a good documentary on him, it gives a real flavour of New York in the 70's. http://www.bbc.co.uk/programmes/b065tqz1