I'll be jailbreaking after upgrading to 2.0 just for Summerboard alone. Apple predictably is not allowing GUI apps into the App Store... I tried telling people not expect such apps given my experience w/ Steve's manic desire to control "his" UI (not necessarily a bad thing, IMO)...
I've got a v1 iPhone, and like the poster above, if for nothing else (well, besides NES, nothing like wasting time playing NES Monopoly and pwning Gertrude) Summerboard. I love the skins that people have made, and it makes my iPhone MY iPhone.
I also use T-Mobile, so I really can't upgrade until I am sure that it will allow me to use the phone unlocked. I am waiting with bated breath for this one.
yes, I never really made use of the apps I had on my JB'd phone, so I checked out 2.0 Its pretty cool, but nothing I couldn't live without. I picked up a couple of programs that let me kill time better (Reading about news and sport and whatnot) that I aren't any different than making a WebLink.
Its still pretty cool though. I only kind of miss my SummerBoard. It made my phone unique, but I kind of like the stock look as well.
i have a bunch of apps i don't use that often but feel i should have...so its jailbreak or bust. customize, wallpaper, and springboard are my most used apps. i get bored and change the look of my phone constantly. until Apple decides to let us use themes and wallpapers im sticking with a jailbroken phone. thats my $0.02.....buy with it what you can