Hi Wizball,
You're right it is a minefield out there, but you can do some things to make it a bit easier. I would suggest trying Wonderland Models or Hannants or Hobby-boss as websites you can look for what you require first. While there are some really good model shops out there they are becoming a rarer and rarer beast these days.
With regard to a subject to build, you're absolutely correct that in terms of ships 1/350 scale tends to have the biggest choice and also the biggest choice of upgrades and PE. With regard to question about tooling, this is where the internet comes into its own, enter your choice of ship on a model site or Mr Google and when you open the description of the model it will say new tooling if that is the case. New tooling is not always a given with any model and happens for usually specific reasons.
As to subject, you could always try a mayflower corvette from WWII or something from 'The battle of the river plate', one of the British cruisers or the 'beast' of Commodore Harwood the Admiral Graf Spee. Hope this gives you a little food for thought.