The Preppy is the best for first timers. Platinum nibs are conistent and the cartridge/converter system is the most veritile of all the filling systems. It's a good baseline to gauge what you prefer.
I just can't recommend springing for the converter though. Platinum converters cost more than the Preppy. Their cartridges are sturdy and can be reused if you clean them out. I recommend picking up a blunt tipped syringe and refilling them with ink samples or from bottles.
Oh there are so many! Just pick a color or shade and there will be dozens that people swear by. Just be careful with shimmer inks since they can clog up the feed. They're fun and pretty but need a little attention.
I recommend checking out a few ink review blogs to find a handful to try. "Mountain in Ink" and "Fountain Pen Pharmacist" are two I follow. Places like Goulet Pens and Pen Chalet sell 4 mL samples for a few dollars which can last you a while on their own. Which is a great alternative to spending anywhere between $8-$60 for a bottle of ink.
As far as specifics: you can't go wrong with the Pilot Iroshizuku line, Diamine inks is another good one, and I think Sailor makes a lot of really nice ones.
Also from someone relatively new to fountain pens here are my paper observations:
Flexbook Adventure Notebook - 85gsm paper - Found to be very fountain pen friendly and tends to suck ink into the paper making it dry quickly making it good for fast writing with minimal to no bleed through.
Leuchtturm 1917 - 80gsm paper - Nice to write on but ink is slow to dry and dark in bleeds through (lighter inks may not be as noticeable).
Moleskine - 70gsm paper - Not recommended for fountain pens, the paper bleeds through if you even breath near it, feels scratchy while writing and can cause feathering with certain inks. The paper would be good for pencils though.
Rhodia - 80gsm paper - Nice paper to write on, has a slight scratchy texture that feels strange when first using it but you get used. Barely any bleed through with dark ink and dries pretty quickly.
R by Rhodia - 90gsm paper - This is their premium paper and although it has the same features as the normal Rhodia 80gsm paper if you can get this version I recommend it.
Midori - ??gsm paper - Haven't tried this paper yet.