Well, this is a very subjective question,
What is your lighting, how much time do you have, etc., etc., etc......
Kodak Portra 160VC and NC are great films meter at 100 and run normal
Portra 400NC and meter @ 250 and run normal. I was not a big fan of the 400VC
Fuji NPS is also a great film. The fuji 800 color film metered at 640 is wonderful and pushed to 1200 also looks great!
Kodak Tri-X 400 not the TXP which is rated at 320. It is a little flatter to me.
Ilford if you can find it. Did they not go out of business?
With the RZ there is a ready load holder that lets you use 4x5 film in the RZ, it is like the 545i holder for 4x5. Gives you a 7x7 negative which is amazing.
Chrome can work but in a very controlled environment. A little too sharp for me. In landscape and still life there was nothing better than Kodachrome and Fuji's various chrome films.
An RZ w/ 110/2.8 and Portra 160VC rated at 100 is a spectacular combination. Look at probably 80% of the editorial photography that had the ability to rate at 100 in their shooting environment before digital and when 160vc came out. It was probably the most used film.
Portra 400NC with available light and rated at 320 and pushed half a stop in processing is simply amazing! Using scrimed Kino's for portrait with this light is so amazing!
Best of luck with film. It is some amazing stuff. You can get yourself an Imacon scanner for around $2k now a days and there is no better combination.
On Digital.
There are ton of choices out there. You can get Valeo's if you can deal with shooting tethered or to their caddy. But the Valeo 22 is pretty amazing for the money.
You can get yourself an Aptus, 22 or 75 again it is all about budget.
With Phase you have the P25 and P30 as well as the P45. Again, very subjective to budget.
I am a Phase user and have been for a since fall 2005 and jumped over to Leaf for a bit and came back to Phase.
Phase right now has really pissed me off with the lack of support for Leopard. Not sure what they are thinking. Leaf has seemed to have figured out their problems. I wish I still had the Aptus75 at the moment, especially at 400. Phase is not good past 200 on full frame chips.
The P30 I have no experience with, so I can't comment. But a lot of people seem to love their P30 at 400 and even 800.
All the Best!