I am going to ask a couple of questions which you don't have to answer here but should think about before buying anything.
First if this is my first machine what do I want it to do?
a. cut grass only
b. cut grass and do all of the lawn/yard maintenance jobs
c. relandscape the entire yard and then maintain it
d. I would guess some combination of the above
Now also think hard and be truthfull as to your mechanical abilities and the amount of time you are willing to commit to upkeep of the unit as well as the $$$$ you are willing to spend in maintenance.
Also you stated a "first lawn tractor" is there a master plan to buy a bigger machine in the future if so what is your projected budget for future purchase?
I recently faced these issues and decided for the money, both now and in the future, that to buy a late model low hour John Deere 318 would by the best I could do. Don't get me wrong it did and will need things but I have the necessary option of fixing them as time and money permit, and especially with all of the excellent help available here and on other sites, it is not too terribly difficult. This also goes for attachements and implements.
The other thing I like about the John Deere 318 is that it has power steering with easy throttle (which acts as a cruise control) and an hydrostatic tranny.
As to yard size, we have 1.25 acres, the backyard has a swale to it and there are trees a garden a pond and play areas to deal with. I have a 46" deck with the power flow bagging 7 bushel system. For my yard if I mow every two weeks then I end up with 1.25-1.5 bags of clippings. 3 weeks equals 1.75 bags and 4 weeks I am dumping twice.
Sounds to me that this setup might be something for you to consider as the unit is highly flexible and build like a little tank.
Here are two links to further your information
http://www.deere.com/en_US/homeowners/products_non_current/series/300_series.html
http://www.weekendfreedommachines.com/
Chris
PS The 318 also has a very good resale market if you do decide to get a different tractor.