Agreed.
At one time I really felt '08 to '09 was superior because figures were unilaterally SA and you got to build free figures, more or less, and all that jazz. I still have a gallon ziplock of BAD parts I'd love to complete droids with.
But 2007... One year, and Hasbro went batshit crazy on character depth and breadth of the line. Not only were the main figures things EVERYONE wanted, but even the Legends line was nothing but hit after hit after hit... Pit Droids, Imperial Officers (crewmen), etc., etc.
As a single line, a single year, 2007 is the top.
Now, that said, as an overall offering... I think '08 to '09 wins in that it was not only the main line packed with greatness, the BAD, but alllllllll those exclusives, the Evolutions, the Comic Packs...
2007 cleared up so many wishes though. Hermie Odle is all one needs to look at and say, "Holy cow, they made that dude?", and it's not just because he's weird, and obscure. It's because he's absurdly huge on top of it all. He is a single figure who epitomizes that year, to me.
However, the sub-line that epitomizes 2007, to me, is the McQuarrie Concept line of figures, which are to this day my only carded collection I actually appreciate and would want to display. If you told me in 2000 that in 7 years we'd get basically a super articulated line of ALL McQuarrie Concept Art figures, and they'd really make a nice single collection by themselves within a year of figures that are just all really amazing and fun, then I'd have said you're nuts.
2008 to 2009 though, equally expensive. Just spread across a whole lot more stuff. I mean, I was so broke in those 3 years, and most of 2010 too.
Prices started going up, and that's where the real issues started. Ultimately Hasbro can only combat that so much too. I think they really haven't wanted to abandon 3.75" as a scale, but the fight to hold onto it is really evident when you look back at this relatively recent history on the line.
I'm really curious to see where things go from here. It's the most uncharted waters this line has been in, in quite some time.