Yeah, it's a fun ride. After watching Eccleston's run, I went back and started from the very first Who stuff I could fine, and have tried to watch them straight through in chronological order.
A few bits of advice:
- Watch out for subsequent releases. Meglos in the Tom Baker era is coming soon, and I think there are still few other serials from the Tom Baker era and onward that are going to be hitting eventually. A good bet is to see what was released on VHS because you KNOW it'll eventually make its way to DVD. The Third Doctor's final outing in Planet of Spiders, for example, was out on VHS for years, and then only just came out (or will be coming out soon) on DVD. You can always go back and catch up, though.
- Watch the extras! Most of the time they're pretty good, especially the behind-the-scenes stuff. There are a few that are a bit crap, though. I'm sorry, but I don't buy that Magna Carta was the first modern exercise in representative government. They tried to make an argument about that in The King's Demons (which is an interesting failed attempt that pretty much typefies the worst impulses of the John Nathan Turner era. And trust me, you'll know what that means by the time you get there).
- Watch with the info text. It's fun, and actually has some funny moments. It's also pretty informative, much of the time. I was watching The Seeds of Death (early 4th Doctor adventure) thinking to myself "Man this is JUST like the plot of the Thing!" and about ten min later, the info-text subtitles explain that they purposely adapted the first two episodes of that serial from The Thing!
- As I mentioned, there are a few serials yet to appear. I think there are one or two Seventh Doctor runs, maybe one or two Fifth Doctor runs, and I think a few odds and ends of the Third and Fourth Doctor. Pretty much everything that could be salvaged from the First and Second Doctor has, I think, been translated to VHS or DVD. The First and Second Doctor eras are the ones missing the most (and unfortunately have some of the coolest episodes).
As far as general observations, in spite of the obvious budgetary issues that always plagued the series, I think that the First and Second Doctor eras had some of the most ambitious stories. It may also be that they're in B&W, but I tend to give them a bit more leeway than some of the "Oh look. ANOTHER gravel pit doubling as an alien planet" reactions I have to Third and Fourth Doctor stories.
Anyway, it's a great ride. Enjoy!
P.S. If I happen to be the guy who's hanging on to that one disc you're waiting on in your Netflix queue, my apologies in advance.