It is hard for me to see any advantage to this workflow, other than to use Lightroom's file management capabilities. One can get beautiful images straight from C1 with very little effort. LR3 offers some local editing tools, but for that kind of work, I much prefer using PS. I find that working in CS5 with the Nik plug-ins is actually very fast and efficient and can achieve results far beyond what can be gotten in LR. Of course, this requires an investment in the Nik Suite, which some may consider expensive, but which I consider a bargain given all of the wonderful tools you get with it. I realize that there are those who shun plug-ins and prefer working from first principles in PS, but I am obviously not one of them.
What ever the processor makes the best file great, thats it. Even C1 does this "SESSIONS" business...what? shoot process, save file as 16bit TIF, edit in photoshop save another for jpeg client view, and when all is done one in PDF, or 8bit file for client final...DONE! Non distructive? your Raw is the raw...your processed file is edited...Done...go back to the raw with latest adjustments and rework if need be. This way you are guaranteed the original file will not be overwritten and its always safe(as long as you have it backed up).
So, I agree with Robgo2's approach ... I have purchased and upgraded LR3, and I find the entire idea of a "WORKFLOW" to process a file odd, and may fit some users but not for me in a commercial photography use.
I use ACDSee for browsing and metadata, etc. C1 to process, CS5 to edit, InDesign for the layout if need be, Acrobat to proof and send to RIP...Done. LR3 whats to teach you a new way of using a computer...maybe it has advantages...?Even Sessions in C1 I get tangled in sometimes and bypass at all costs.
Just do your job software...don't get ambitious....but do the job you were designed to do exceptionally well!....I use C1 5x for processing...But still use C1 3.79..its just not bloated and full of stuff all over. files viewer focus window...DONE. LR3...still waiting on sidelines. IF you are gonna use a plug or what ever and make drastic changes It belongs in editing...CS5...not processing....for me....as I can see landscapes (hence the title of Michaels realm :-) work well for LR3....not commercial use.