How exciting to be at the beginning of your journey!
I would absolutely echo the 'best ground you can' sentiment. I am lucky enough to live on an upland farm of several hundred acres. We keep a few pigs on the side of our commercial beef and sheep enterprise, but in truth our ground isn't suited to pigs; it's too wet - "severely disadvantaged", all of it.
I would think 5 acres of
good ground would probably be pretty tight if you want cows. (You can't keep just one, they need another of their own kind for company, as do most species.) Others who are at that end of the spectrum will be along to comment in due course, I am sure. One thing they'll tell you to think about is whether you are happy to buy in your winter forage (hay, silage); if you want to make your own you'll need ground for that too - although sometimes you can buy a 'standing crop' from a local farmer, which might suit you. And if you are thinking about livestock, you will want buildings for storing fodder and for winter housing - they're expensive to build and need planning permission, so it'd be better to start with holding that has a byre and a barn if possible.
As to other reading - have an explore of the books listed on this site
http://www.accidentalsmallholder.net/books/ (there isn't a tab for Books, must mention that to Dan...)
If you haven't come across it yet, the John Seymour Complete Book of Self-Sufficiency is a great book. I'll stick my neck out and say it's completely infeasible to do what he outlines in 5 acres, and some of what he advocated in the orginal version is now illegal or considered inhumane - but it's still a grand book for a really good intro into every aspect of 'The Good Life'. As the review on this site says, "Every sentence not only useful but interesting." Just make sure you read it with a very healthy helping of scepticism.