Whats your budget?
Mont Blanc is sort of the gold standard.. its the writing instrument everyone will recognize, know what it is, etc.. They are a fine pen IMO, but are a little bit overpriced I think.. but they can pull that price because they are far and away the best known and most recognizable brand in quality fountain pens..
That said, there are several options that are equally if not even nicer IMO (a lot of this is driven by taste) that can be had at a similar price point.. I particularly like Visconti.. They are made in Florence, Italy and have a more "Italian:" flair to them..
Pelikan, Aspinal, Waterman and a few other brands offer quality instruments that are typically at least 1 to 2 steps down in price from Mont Blanc or Visconti..
There are some great options in terms of writing quality that are very reasonably affordable from parker, lamy, and others..
I stacked up quite a collection of really nice old, vintage parkers and other pens for peanuts just watching auction sites like hibid and ebay at different times....
Its easy to spend north of $1K on a pen if thats what you want to do.. Ive got a couple of pens that new would retail pretty close to that number.. but, truthfully, you can find yourself a pen that will write really well, be comfortable in the hand, look nice, etc.. for well under $100 if you are willing to go vintage and take some time searching... and a brand new Lamy Safari is just $37 from the Lamy website, and is IMO the best "starter" fountain pen on the market at a price point that makes it affordable to everyone... I have several Lamy's that I use all the time.. I bet Ive accumulated a dozen or more of them over the years between my wife and I (I got her into using fountain pens probably 10 years ago and bought her several as well)..