A good way to make a toned-down NPC version of any class is to multi-class it with Commoner.
Bandit: Commoner + Rogue
Thug: Commoner + Fighter
Cultist: Commoner + [insert spellcasting class(es) of your choice]
I gamed when I was in the United States (fave gaming memory of those days was running Tomb of Horrors on a Greyhound bus to Albany). There used to be a store that sold gaming supplies on Staten Island and I also recall finding another one just down the road from the Empire State Building in New...
No no no no! Either you have actual character death, or PCs suffer no adverse effects whatsoever, ever!!! It's one or the other! No middle ground!
Sheesh, some people don't understand that everything is black and white with no shades of gray... :D
I voted for the Psychic Warrior this round; it would be silly to vote off the Psion and keep its hybrid cousin.
As to who'll be left over at the end? I prediict it'll be the Archivist, Duskblade and Scout.
Conjuration. Extremely flexible, with a broad range of offensive, defensive and utility spells, many of which have multiple uses -- glitterdust being the cardinal low-level example. And let's not forget everything you can do with summoning spells; high-level summoned creatures can blast...
Don't forget that you can balance things by giving the NPC some of the same spells as the PC wizard. Figure out how many new spells you want the PC to acquire first, and then flesh out the NPC's spell selection with spells the PC already knows.
There's nothing especially wrong with the Marshal. It's just that more people are familiar with it than they are with the other classes on the list, because it's up on the WotC website for free.
I've finally gotten a chance to see the text of dimension hop in the PHB II, and it's a lot more powerful than I'd have expected. It's a touch spell, so you can use it to transport party members instead of yourself. Moreover, it can be used on unwilling targets. So you can move an enemy over...
Note that you can maintain some of the benefits of magical items in a low-magic-item campaign by allowing for a broader range of effectiveness for masterwork equipment. I know there's a system for this in the Black Company campaign setting book, and there are probably other books that do the same.