Light, Nova Swing and Empty Space by M John Harrison are all set in the same universe. I'm not sure it's "space opera", but well worth a read if you like intelligent, challenging and thought-provoking writing.
I went to the Barbican's sci fi exhibition yesterday and thought that there might be a section on space opera. There wasn't really: they had a stab at themes, rather than genres. It's well worth a visit before it closes at the end of the week - especially to see the props, suits and Harryhausen models / sketches.