One might take a quick look at the Bad Pitch Blog and begin to understand why many journalists think of PR people as a mere annoyance, or even worse, an obstacle between them and the potential source of a story (aka: the client).
Public Relations India has a list of "What journalists hate in PR people" that consists of several journalist pet peeves. Most of these should be pretty well known by practicing PR professionals, including not respecting deadlines, following up on releases with no new information, giving gifts to journalists and sending irrelevant pitches and releases. The complete list, along with the comments that follow, is well worth a read.
Owen Lystrup at Into PR also took note of the rash of blogs and Web sites pointing out what journalists "hate" about PR folks, and suggests the possibility of surveying journalists about their experiences with PR. I like the idea, and would be very interested to see the results of such a survey among reporters I’ve worked with… And even those I haven’t, actually. (Are the results of such a survey available anywhere on the Web?)
Overall, most of the journalists I’ve worked with in the past have been
very friendly people who appreciate a relevant, newsworthy pitch. It’s important to learn what constitutes such an approach, and strive toward becoming a trusted resource for reporters rather than be regarded as an annoyance.
UPDATE: Valleywag has another list of "Tips for PR workers from the journalists who hate them." My favorite – "Don’t be creepy." Good call.

Thanks for the link, Eric. And thanks for the insights.
I think you and Richard Millington have a good approach. Finding the appropriate way to contact someone is a good first step.
So far I haven’t gotten any results from anyone that has done a study; but if someone points something out, I’ll definitely post it.