I played ME1 and I'm about to start ME2...any suggestions on which class to play and how to spend my points when I level?
Well, my fave build is using an Adept.
Bastion/Heavy Warp/Heavy Singularity/Heavy Throw. As I usually play on Hardcore or Insanity, I also usually max out either Geth Shield/Fortification/Barrier.
I use Miranda or Garrus and the Arc Projector for Shields. I Max out Zaeed's Squad Disruptor Ammo, for all geth levels.
I feel that the classes changed drastically since ME1.
I also feel that choosing a class is essentially based on personal preference.
For instance, I choose the Engineer class because it does more to disable and expose the enemy (Overload, Incinerate, Combat Drone, etc.).
That's just my opinion, of course.
If you haven't already chosen a class, here's some class "trailers" from BioWare that describes each class in depth.
Apologies ahead of time if the links don't work.
Hope this helps.