Welcome Steven. I'm not Ken but I'm a life-long O gauger living in the Land of No Basements and I feel compelled to weigh in. It's my opinion that if you're building a spare room-sized railroad and you want something that will provide varied operation long-term, you would be better off using sharper curves. IMO in a room that size, probably no bigger than O42.
It's true that you won't be able to run many of the coveted scale locos like Berkshires and articulateds. (And that might actually save you money in the long run!) But if you do build with O60 and O72, the only track plan that will work is some variation of a double-oval. And really, just an extended circle, because curves that wide won't leave much left for the straightaways. If you just want a stubby test loop to run and photograph trains from a closet collection, I guess that's ok. But for all of the money, time, and effort involved in constructing a good layout, I strongly encourage you to imagine the more interactive track plans you would be able to build by using O31 or O42 instead.
Years ago I would have endorsed the wider curves because the scale-sized locos tended to run more smoothly than the toy trains we grew up with. Now, we have RailKing with PS3 and LionChief Plus, so that's no longer the case. This hobby is full of compromises, notably the third rail itself. And if you must have a "scale model," many switchers, Moguls, Ten Wheelers, etc., are scale-sized and will still run on sharper curves. Everything about tradtional-sized trains (including Plasticville buildings, shorter rolling stock, etc.) is optimized for a smaller space. Honestly, if I hadn't been in O gauge all my life, I would build in S because 3/16" scale is still big enough to see and work on, but closer to optimum for an 8' x 12' space.
Everyone brings their own experience to the hobby. For years I participated in modular public displays. Personally, I'm done with round-and-round running. Some people just enjoy building layouts; for me it's about what you can do with the trains after it's built. I'm not going to put a lot of time and effort into something that's going to leave me bored and collect dust after the first 6 months. It's your time and money, think hard!