Apples? Varieties recommended

I am wanting to buy a fruit tree for my garden, an apple, but I'd like some advice as to variety?  How can you pick one without tasting them!

From supermarkets I like granny smith because they are crisp and crunchy, I cannot stand golden delicious because they are just all pappy in my opinion!  I really do not like any apples that are not crisp and crunchy at all even if the flavour is nice.

Oh and if possible I'd like it to look reasonably nice as it is going in the centre of my lawn :o)

Probably needs to be self-fertile as we only want one but having said that next door has an apple tree but no idea what sort and haven't taken enough notice to know when it flowers.

Go to an apple day, usually held during October.
Some (not all) have tasting.
List here.

There are loads of types of apples that are not sold in supermarkets because they either bruise easily or have a very short shelf life even though they are initially very crisp and crunchy and so are brilliant straight from the tree.
Then there is the size of tree - mini trees on dwarf root stock (easy to pick and take up less space) or a bigger tree ( more apples ) 
Other things to consider when buying are when they flower  as some need more than one pollinator so you must have trees that are flowering at the same time, but you do not necessarily want them cropping all at the same time!
So all in all trying to find an apple day is excellent advice because there is lots to consider and you should find expert advice there.
A favourite of mine is James Grieve - super tasty and very reliable 

....so its pollinating group can be identified. 

Good idea, although if you are in an urban area then chances are there will be a lot of other apple trees around for pollination anyway.

My own favourite apple (modern variety) is Falstaff.

Here's a link to the Keeper's Nursery page for Falstaff: LINK. You'll see at the bottom the link for pollination partners.

Also, there's a useful article about apple rootstocks here. I would think a tree on M9 or M26 rootstock would be best for your lawn. Most garden centres should stock them.