Well, it really depends on what is most important to you:
If you are more price conscious, and you don't mind needing to check the app rather than looking at your wrist to find out how you are doing, a Flex will be fine.
If you have a higher budget and want something all singing, all dancing that is more of an all round smart watch, get a Blaze or an Iconic - they're great devices, but the two downsides are cost and size - they are both quite bulky. That said, you get really good connectivity and notification capability, better sleep tracking and things like silent alarms, loads more besides that I can't remember off hand.
If definitely you want a visual display on your wrist, but you still want something that looks more elegant and don't mind losing a bit of the smart watch functionality, look at either an Alta or a Charge. Both are much more slimline and (to me, anyway) attractive, but the Alta doesn't do floor counts or have the heart rate monitor as standard (though you can pay extra to get it). The Charge has both, and also has GPS, but it is more expensive than the Alta.
From your OP, it sounds like you're not really bothered about all the sports/enhanced functionality, so personally I would look at an Alta or a Flex depending on your budget, certainly an Alta if you can stretch to it. I have both a Blaze and an Alta, and I do prefer the Alta.
One tip if you do go for an Alta, the Fitbit branded straps are rubbish, they constantly fall off - but you can buy really nice non-branded ones on Amazon for £10-£15, which I would definitely recommend.