Pick what you will. Lots of good product out there. So I'll offer this:
Wireless is nice, but eats more batteries and is a bit fussier.
HR is great, like a tachometer for your body. On my roadie I won't go without.
Cadence is great as well. But once you find yourself looking at the cadence saying 'gosh I was only off by 3rpm' on a regular basis, you don't need it.

So what (data) do you need? Want?
No HR/Cad means a nice, cheap, durable wired model.
Otherwise you're in for a $100 or so for a nicer, more complex wireless job.

Polar and Suunto have some watch based models as well. Suunto T-3 or T-6 catching my eye, but spendy. Better for multi-sport folks.