rofl - I was going to suggest clogs, but the image in my head of Marcos in high heels trying to walk 10 miles and the state of his feet and the rest of his body afterwards just doesn't bear thinking about - let alone the comments of motorists and passers by as they view his well sculpted calves!
I've walked a fair few miles in my time and 10 miles is quite doable by people who have done very little exercise previously, (not that I'm implying that you are a fat lazy b'stard!). The key component is footwear as you've spotted, but also how well that footwear is worn in and how well suited it is. It's always best to have a pair of shoes, trainers or boots that you have done a reasonable deal of walking in before you attempt a longer walk. If you have new shoes then you'll have pressure points that will become very, very, sore on a long walk like 10 miles - many an army recruit will testify with bright shiny new boots, so wear in whatever you buy. I used to wear new football boots as often as possible pre-season - even in the house as a child (they were clean, moulded studs and the practise was approved my mum and insisted on my my dad), working the leather with my hands and flexing the sole so that when it came to practise and the first game I wouldn't suffer.
Overworn, knackered trainers or boots are just as bad as brand new unused ones. They just won't support you properly over 3 miles let alone 10 miles. However, you may well complete the 10 miles and think, "sod this!", so it's probably best to look at the footwear you have available at the moment and assess how comfortable the shoe is going to be. The likelihood is that you'll get some blisters, but they won't be really bad if you have some decent trainers that are worn in and not past their sell by date. If you've got nothing suitable then it's gonna be a be a question of buying something suitable that you can use anyway even if you find you don't want to do alot of walking. In that case a trainer-style is gonna be the way to go.
I've always measured a good shoe by grabbing the front part and bending it upwards so that the toe will contact or get very close to the top of the heal. The sole shouldn't flex too much the other way; just enough for a natural downward curl of the toes. (As an aside I've seen modern football boots able to flex completely to the heal in this opposite direction and I believe that this contributes to the increased number of metatarsal injuries we see of late). I then look at construction - how well made they are. You've been wearing shoes for most of your life so where do they wear out quickest? (Isn't English great? - wear, where, were). Is it the uppers, soles or stitching? Look at your shoes and see where these problems occur. For example - I've got wide feet, big, big toes and I walk on my inner-heals (yes I'm a Hobbit) so I'm aware of where I'm going to wear a shoe down, i.e stretching the stitches across the widest part, toes wearing away the upper from below in the big toe area and wearing away the heals on the inside. I have v wide feet, as do all my family, so getting a good fit has in the past been difficult, but now we're spoilt for choice.
You can get inserts that will mould to the shape of your feet so if you are looking at doing this regularly then this is an area to look into.
I have favoured a light weight walking boot with a semi-flexible sole. A friend and myself went travelling 10 years ago and pucka walking boots (waterproof) were the best purchases we ever made. He went for a semi-rigid sole with a deeper tread and high quality goretex upper @ £150 (that would accept a crampon) and I went for a more flexible sole, lighter tread with a goretex upper @£100. We both still use them and I've walked 10 miles on tarmac a good few times in them since. The trouble with doing that is that the boot feels stiff and quite heavy (compared to what I usually wear) even though they have been worn in and will cause me the odd blister, because I don't do that so much now, but more frequent use would alleviate that.
As for trainers I've not done much walking in trainers, but I would look for good ankle support if I was looking at doing 10 miles along with comfort and quality of construction regardless of brand label. No point being lame in expensive, posing trainers after 7 miles. Fashion in this case is entirely beaullox! Hitec used to do a trainer that extended up the ankle (but not constructed or styled like a basketball boot) that was a sort of an extended trainer with a partial walking boot sole that proved extremely popular in the early 90's - can't remember the name of it. Something similar might be a good choice if you do take it up and want to use them on road and off. The best thing to do is try on loads and loads of shoes in different styles to see what is the most comfortable to you, wear them in and go for it.
If you plan on walking mainly on tarmac then favour a trainer design as this will be lighter, more flexible and comfortable. If you are looking at hiking/off-road then go for a light-weight boot design with a flexible sole that will give you the additional ankle support.