Should I Stick With PunBB for my next project or Switch To vBulletin?

Well, it all depends on how many modifications we're talking about. If you could run PunBB with one or two mods, I'd say that's  a viable alternative. If, however, you need to apply 5 or 6 mods in order to get the functionality you need, I'd go with something else.

It should also be noted that the extension support in 1.3 will make life a lot easier. We'll have a couple of officially supported extensions (for popular items such as PM). You can expect these to be of the same quality as the rest of PunBB.

I think you should go for SMF. Don't get me wrong, punbb is by far my favorite forum software and i recently start to contribute with modules. But there is an issue on modules usage that i faced in the past and it's damn anoying.
If you have like 5 or 6 modules, when you update you will have to do the hard work over and over again... and some modules require going on the line 304985 of the file whatever.php and replace "xpto" by "sputnik".
If you need more bells and whistles i strongly recomend you SMF. The base core of features ( too many for my taste ) should do it. So you can easly update without any trouble.

Personaly, the thing i like with punbb is the right amount of features.... not too simplistic and not to barroc. If your comunity is not i dont think you should force it on it.

That's the main reason I've stuck with one app per purpose. It's easier to stay current if all your forums run the same app or your front ends run the same CMS. Heck, just staying current with 4 or 5 main apps is a task in itself, throw in different apps per domain and you're asking for a headache.

A pleasant side effect from standardizing on certain apps is that it's very easy to launch new domains at will.

Hey kids,

Since I started this thread I'm going to dig it back up with an update and a bunch of questions.  I ended up going with punBB for my recent project and so far I'm mostly glad I did.  There are moments that I wish I had all the bells / whistles of vBulletin, but I'm afraid the resources required to run a big forum on that platform would have been too much for my budget (hosting costs, not the software).  With that said I'm realizing that for some of the members of my new community the bells and whistles are more important than speed and performance.

So, here I am running punBB with a pretty busy forum.  I want to start adding more mods but have been holding out for version 1.3 and the magic extension system.  The "big" mods I'd love to add are:

Mark Topics Read
Easy Poll
Private Messages

From what I understand "mark as read" will be built into the core and the other two are first on the list for "supported extensions".   The big question I have is do I install them myself (very manual / difficult process) or wait for 1.3 and extensions?  Here are my issues / problems / concerns / thoughts:

1)  1.3 may be 3, 6 or 12 months away... nobody knows.  From what I see, the early discussions of 1.3 go back to January of 2005
2)  Even if 1.3 was released tomorrow it would still take time for the dust to settle and for the extensions to be built / tested

So, with this uncertainty I begin to go down the path of installing the existing mods manually, but this brings up a bunch of other issues:

1)  We all know it is just a pain to manually hack the code to add mods
2)  I'm not php / PunBB savvy enough to know which mods will break / effect other mods where and when.  It scares me to death that I'll follow one of the "Replace this line with this line" instructions and kill an already installed mod or cripple my forum.
3)  Lets say I magically get all the mods working together (like smartys has on his cool PunBB hosting site).   Well, then I'd be worried that ever time there is a PunBB security / version release that the patch files that have worked flawlessly thus far (knock on wood) would stop working because of a "heavily modified forum" and I'd have to edit all the updates manually... blah. 
4)  What if one of the mods causes problems on my server (for example, hogging resources).  If you thought manually adding a mod was a pain, try hunting through code to remove it!  This is one of my biggest joys of an extention and being able to add / remove seamlessly.
5)  Once 1.3 rolls out with all the cool extensions, how  difficult will it be to upgrade to 1.3 and then clean up all the hacked pages and integrate / load the cleaner extensions?

So, where does this leave me?  Should I have gone with vBulletin originally?   Should I make the switch now?  Should I install the mods or wait for 1.3 and extensions?

I seriously look forward to your comments & suggestions!

Just some thoughts on this:
(1) Indeed. It's a very primitive way of doing things. Tedious, risky, in-elegant. Very un-2007.
(2) and (3) and (4): The way I work through these issues is:

(a) even with my limited knowledge of PHP, I try and thoroughly understand what each new mod or patch is trying to do. Worryingly, you often don't have to know much to see that some punbb mods have significant problems that you can often catch before their code goes into your forum
(b) I thoroughly document every mod and code alteration that I make so I know what I did to what page and when, which mod modified the database  etc;
(c) I maintain a 'dev' punBB which I build any mods, security patches or tweaks into first, with all the 'reveal queries' config switches on, and then if they test out and work OK with the existing code, they then go into my production punBB codebase;
(d) I never use automated patchers or diff toools. I manually apply all updates using tools like WinMerge. Things will be guaranteed to break otherwise, and it gives me the chance to eyeball every proposed update.

As to (5) - good question. At least I am pretty confident that I know all of the mods and alterations I have done, so I expect that will help in stepping across (carefully) to 1.3.

As to VB - in some ways it faces the same problems as punBB here. If you make any hacks to it or apply non official VB mods/themes, you'd face may of the same issues in keeping it all working across VB version upgrades.

I guess where VB and other more fully featured forums save you some hassle though is that they have most of the features built-in that may punBB users have to rely on mods and hacks to achieve.