Ok, ask yourself. Why do you think you need a new camera? Is your current camera not good enough? Why? What do you shoot?(I think all 3 systems are capable of satisfying most users) If you can't answer this, then you probably don't need a new camera because you NEED it. You need a new camera because you WANT it.
Kit is right, your X-700 is as capable as any other camera, provided you use it properly.
However, I suppose you're considering upgrading to an AF system. Depending on which class of AF bodies you are looking at, some are no better than a point-and-shoot which severely cripples your creativity (hey, you HAVE been that X-700, rite?), while at the other end of the spectrum are cameras that will bewilder you with their wealth of controls.
It might be easier to do some things with newer bodies. For example bracketing, film advance and rewind, and not to forget, autofocus (duh!). But if you can live without these features, then stick to your X-700 as you'll see no gain except for that lighter pocket.
And if you so decide that it's time to embrace new technology, don't write off Minolta as a system for professionals. Minolta camera systems are well capable of holding its ground against other much-hyped-about systems.
Go for a 2nd hand low end autofocus system from Minolta. Maybe a 505si or a Dynax 5 (if u can get it). U will probably have to fork out about $400 or so. Try TCW. No idea what lens u are using now but a 50mm f/1.7 prime would be a good and cheap and sufficiently versatile lens. I stuck with it for a while and found it very helpful. It's encouraging to get pin-sharp photos first time around on an SLR and the 50 is really sharp. Be prepared to pay about $160-170. Trade in the X-700 and maybe knock off $200 or more from the total cost here. Your choice. Haven't regretted getting Minolta though. For one thing, it tends to be cheaper - whether first party or thrid party lens - that's a plus point for me.