I'm happy with what I have, but it may not be what you want.
What do you want ot listen to?
Some older scanners will go up into the 1000 mhz range, allowing you to listen to more things the avaerage people would be able to hear. (analog cell phones are the first to come to mind)
Listening to aircraft frequencies can be interesting.
Some older scanners will allow you to listen to cordless phones on both the low band vhf and the 900 mhz uhf.
Technology has limited what many scanners can do when it comes to listening to law enforcement. Many large departments have adopted trunking systems which the average scanner will not be able to pick-up. If you want to listen to these, it can cost quite a bit of cash for a scanner with this capability. At the same time, many police department have not yet adopted these systems due to the $$$ involved in the change over.
You'll need to decide what you want to listen to, do some research and go from there. An external antenna can also be a great investment.