The HTC Desire is the best Android handset if you want the Sense UI (that you've tried on the Hero).
The Samsung Galaxy S is a very impressive device, so I would certainly recommend going to have a look at one of those.
The software will look different than the Hero you have tried due to it having TouchWiz and not the Sense UI.
If you like the HTC Sense UI, then you'll want a Desire.
You could consider the X10 if you need a slightly better camera but you would be sacrificing far more in order to get that, and most likely paying a lot more too.
You are right to look at Android and not the iPhone due to far far more than the price point but I imagine that is a major point for a lot of people
The best deals can usually always be found between these two websites, so have a look here -
http://www.mobilephonesdirect.co.uk/
http://www.mobiles.co.uk/
All in all, go and try both the HTC Desire and Galaxy S, compare the software on them, bearing in mind that technically the Galaxy S is a slightly better phone, so if you like the software on that, go for it.
Any questions about anything, ask away!