I'm a firm believer that it's very hard to get one piece of gear in a category that "does it all". For example, a very lightweight summer sleeping bag saves weight and bulk, but then a shoulder season bag (early spring and late fall) is needed for some trips, and an even heavier bag for all out winter. So rather than getting 3 bags, many buy a bag that can handle down to 20 or 30 degrees F, and get a winter bag if needed.

Of course, the other side of the coin is watching the budget—which most of us have to do. Most people can't afford the best piece of gear for every possible trip scenerio. Buying used can always assist acquiring more options.

Then there's also the educational aspect of all of this. As we get and use new gear, we learn over time what we like and don't like, and thus how we want to adjust our gear closets.

I think you've made the right decision for now to get a three season tent that will also usually "make do" for the occasional winter outing. That also saves some weight for your most common three season usage.

Good luck, and happy camping!