If I see a guy wearing Ugg boots I feel like laughing, why? (and note, I live in the Netherlands, other countries may differ) Ugg boots were designed for men but women ended up really liking them and now about 9 out of 10 of the ladies here own at least one pair of these (rather expensive) slipper like boots. True, I don't like Uggs, but Uggs on men look wrong to me (and a lot of people I know). We sort of consider them to be slippers you can wear all day and the few ladies that I heard about them say that they are a bit, 'but they're so nice and comfy and warm!'.
Then.. I consider hiking boots to be a good random boot. Steady, comfy, warm and it looks good most of the time. Just make sure you get the light hill walking type and not the heavy hiking type, wearing these daily will make some muscles 'lazy'.
And size, if one would pay attention, I think one could notice in the way someone walks if their shoes might be too big. Make sure they're comfortable, I think it might 'hurt' you in the long run if you walk on oversized shoes daily. Know that you might take half a size bigger if you put insoles in the shoe, but it's not as good as a natural fit.
Also, since you're shopping online. Sizes can be different not only shoes and boots, but also each brand. My converse, skate/sneakers, heavy hiking boots and another set of boots all have a different size. (more or less) Best to buy them in the shops ór, try the brand in a shop and buy online.