For just plain low price, the press cameras can't be beat. But you have to accept their limitations - limited movements, little or no choice in lenses, weight, limited bellows draw. Within these limitations (and they are not as severe as they may look), the press cameras are often excellent.
But my gut instinct is to recommend a 4X5 field camera. If you are mostly interested in studio work, a monorail might be a consideration instead of a field camera. Several are available new at low prices (e.g. the Tachihara). Good examples are also readily available on the used market. You can grow with one of these. They take a wide selection of lenses, and lenses for this format are not very expensive, especially used. You've already mentioned the variety of film available, and the film doesn't cost too much. Most of these cameras will give you all the movements and bellows draw you will ever need, and they are generally quite light weight.
The 5X7 is tempting, however. You can get a useful contact print from a 5X7. An enlarger is not a problem for you (you have a good one for this size). The 5X7 aspect ratio is a bit more appealing than 4X5. The cameras are a bit more expensive, as are film, film holders, and lenses, but not a whole lot. You can usually get accessory backs to take 4X5 film holders in case you really need to use a film that is only available in 4X5. The camera construction for both field and monorail systems is similar to 4X5s, but often a bit more rugged, so all the same advantages apply.
In the end, it's a very personal choice. I would lean toward something you could live with for a long time.
