MGS 3 and MGS 2 and MGS 1. In that order. You already have MGS 2 trainer here for GOG version. Implementing that with update so that it works properly (that trainer has inventory management issues associated with it) for MGS 2 would be great.
I second what Chikushodo stated - the "have all items" cheat doesn't allow you to save your digital photos in the tanker section of the game. Being able to add items individually might be ideal, if possible (specifically stealth?).