Well now, this could get interesting very quickly
There are a lot of cylinder head choices out there now that weren't there even a few years ago.
People will probably tend to recommend to you what they "know" or have experience with. I know I really like the way my engine is built and can tell you all about it - but that's just one example. There are many ways to make power reliably with Pontiacs, so be leery of anyone who tries to tell you his/her way is the absolute best, especially if they can't back it up with logic and real results.
I like roller cams/lifters because you can get more power ("area under the curve") without having to go crazy on the amount of overlap and duration the cam has. Both overlap and duration have an effect on street manners - how rough it idles - and also how much idle vacuum the engine makes. This is important if you have vacuum operated accessories like power brakes. Another reason I like rollers is you don't have to lose sleep at night over whether your oil has enough ZDDP in it and whether or not you're going to be unlucky and have a cam lobe 'wiped' during break in. The down side is that roller systems are expensive, and if you choose a solid variety like I did you'll have to check and re-adjust the valve lash periodically (though not as often as some might suggest.)
One thing nearly everyone agrees on is that the Pontiac factory rods need to go. Replace them with some good quality aftermarket forged rods. You can get a set for not much more than you'd pay to have the factory rods reconditioned. The factory rods are always the weakest link in a Pontiac - with the debatable exception of the 455 SD rods --- but those things are awfully heavy. Plus, replacing the rods and pistons gives you the option of going with the longer 6.800" rod instead of the factory 6.625" rod. That's another 'debate topic', but the longer rod because of the geometries involved changes the piston 'dwell time' near top dead center, piston acceleration, and also the point in the crank rotation where the rod and the crank are at a right angle to each other. Some folks think a longer rod is 'better'. I'm one of them, but I can't "prove" it.
Cylinder heads --- now there's a topic for debate and you'll certainly find lots of opinions. In your situation I'd probably choose an aluminum D-port head, either Kauffman or the new Edelbrocks, just because your car is already set up for a D-port exhaust system and that would save you having to replace your headers (or manifolds - I forget what you have) also. The new Edelbrock D-port heads have some very nice looking chambers. The Kauffman's are similar. People have more experience with the round port Edelbrocks like I have, just because they've been out much longer, but a good head porter can do magic with either design.
Either way, I'd still buy them bare and have Dave at CVMS in Virgina build them up for me. I understand that's not a trivial thing for you to do, but I know you'd be happy with the results. The problem with buying any head off the shelf and ready to run is that they generally come with cheaper springs, cheaper valves, and other hardware that's not necessarily top of the line.
You'll probably have to change your ignition timing some because of the heads. Different chambers, different materials, all effect how the combustion flame propagates through the chamber and that's what determines how much advance your engine will "want". The heads you choose will also in large part dictate which spark plugs to use.
Once you've chosen a particular head and combustion chamber, then that will determine which pistons you'll want to use in order to put the compression ratio where your engine will be happy. I'm not familiar with how octane ratings vary between "here" and "there", but "here" on 93 octane and aluminum heads, I'd shoot for a compression ratio of around 10.2 or 10.3:1
Take your time, talk to people you trust. If you can, I'd recommend giving Jim Lehart a call (+1 434 767 9915). He'll tell you the truth and won't steer you wrong.