London and Dublin: open to ideas

Just as literature graduate students never admit that there are books they haven't read, we urbanist pundits aren't supposed to admit that there are cities we've never been to.  In fact, we're so up to date in our lived experience that there are no great cities we've never been to recently.

Tip: We're all faking it, mostly with Google Earth.

So, to keep up my outsiderish reputation, I'd like to announce that I haven't been to London for 19 years, and I've never been to Dublin at all.  Fortunately, that's changing this month.  I'll be in London March 14-16 and Dublin for a week following that.

What does a transit consultant with North American and Australasian experience do with just a couple of days in London, or with a full week in Dublin?  With whom should he meet?  What experiences must he have?  I have my own ideas, but I love the fact that so many of you know these cities better than I do.  Have at it in the comments!