For a newbie: New or Used??

I've been an Apple fan since getting an ipod touch and iphone 4s. My 7-yr-old Windows PC (15", XP OS) is dying and I want to make the switch to Mac. I'm a very basic computer user: surfing, itunes, blogging, photos, that kind of "lifestyle" usage. My husband has always been my IT guy, and I'd like to kick that habit and learn to manage my own computer stuff.

After visiting an Apple store, I'd pretty much decided I'd get the MacAir but am hesitant about the 13" screen. What I do like about it: its solid-state design--no heat/fan or moving parts; it's lightweight, and it's in my price range. I never use my disk drive so won't miss that.

Then I started looking at MacBooks on ebay. Seems I can get more bang for my buck but am wondering: if I buy a 2-4 year old machine, will I want or need to upgrade to the new Mountain Lion OS? Will I need to? At what age are Macs no longer able to upgrade to the newest OS. I'm asking that as my pc has always been unable to upgrade to windows7.

If I decide to buy used, what system would your recommend based on the above described usage habits?

I've always had a love/hate relationship with my computer but LOVE my Apple products. Who knows, a Mac computer might change everything!

Thanks in advance for your advice.

I think you'd be more than happy with the MacBook Air. The 13" screen isn't too bad and Mountain Lion isn't necessary but if you do want to make the switching it's always possible.

For a newbie/switcher who wants to save a few bucks, I'd strongly recommend Apple's refurbished models. Unlike used machines, they come with a full warranty and are in spotless mint condition.

Thanks for the advice. I started another thread about a used MBP but that deal fell through.

But my refurbished 15" MBP is on its way! My nephew works for Apple got a bit more of a discount so the deal actually ended up being great, and I feel so much more confident buying directly from Apple, with the warranty.

I really tossed back and forth about screen size but ultimately decided the 15" would be best in the long run.

Lori