Andrew has blogged about a common trait of technical speakers where as part of answering a question they re-state the problem to ensure that they and the audience are in sync.

Personally I don't see a major problem with "So . . .", I know that I use it all the time, its a very natural way of restating the question, and if we think of our typical audience being programmers - they would be parsing the presentation for these "tokens" to know how to set their context.

Think of it as programming your audience :)