Great page Catamount - one I've had bookmarked for a long time. Even though I live in Virginia, I have long been enamored of the Northeast mountains and their hiking/peakbagging culture. Of the many lists I'm slowly working on there, the 115 is one of them. I need two in NH and nine in the Dacks.
As far as Lists of John goes concerning the Northeast, as Teresa pointed out - members can add their own custom list to the site and make it public (or keep it private). The main problem is that unless they are named on the map, or it is a county highpoint, the site does not include peaks with less than possible 300' of prominence. This isn't a problem most other places where 300' is the accepted norm to be a "ranked" peak - that is one that would be considered #X highest in a complete state listing. However, John Kirk has some leeway for rectifying this. If a missing peak has an unofficial name published in print somewhere and you contact him with the documentation, he will likely add it. He may possibly also be willing to add a peak lacking an unofficial name if you can document that is is on a long-standing, often pursued list.
Some other lists worth doing are those based on prominence. The biggie in the Lower 48 states is the list of 57 Ultra Prominence peaks (P5Ks) - those are the peaks with at least 5,000' of prominence. All but two are out West. Only a handful of people have done all of them, but you can be assured that nearly all of these peaks are "worthwhile" P2K and P1K are other popular cutoffs. You can work on the most prominent peaks in a given state or a region, like say the Southeast Fifty Finest. See http://www.listsofjohn.com/USPro/USProIndex.php
Similarly, some people like doing county highpoints. http://www.cohp.org/
Many of these highpoints are truly worthless as destinations, but others are great. Like the prominence peaks, you can divide them up into sunsets like the Eastern 50 Highest or the Apex 20 Toughest. I'm hoping to someday complete all the Eastern ones above 3,000'. Still need 26 but I've finished the Eastern 50 Highest, and only lack two for all the Eastern ones above 4,000'. See http://www.cohp.org/indiv/Rickey_Shortt.html
. Some people, like Bob Packard, take this pursuit to a whole new level http://www.cohp.org/indiv/Bob_Packard.html
Isolation lists are yet another set that have the potential to be good, especially in alpine regions. This criteria is based on how far away the nearest higher peak is, so if you are on one, you are on the highest thing around for a long distance. In Colorado, for example, you could do the 23 peaks with at least 25 miles of isolation, or perhaps the Top 25 most isolated from this list: http://www.listsofjohn.com/PeakStats/select.php?S=CO&R=I
Several of the Southern Sixers are pretty miserable, especially in Summer, but there are definitely some good ones mixed in.
Several states also have club based firetower challenge lists too, including North Carolina, New York, and New Hampshire. These don't include every firetower in the state (because of access issues) but they are definitely all worthwhile summits.
Just some ideas and thoughts,