Why not just get a router you like and attach it to the DSL modem? Some ISPs are rather persnickety about the DSL modem you use. And it sounds like you're interested in router features, not DSL features. But hard to tell with the limited info you gave.
I second the above poster's recommendation. It's also important not to confuse routing and modem functions, as well. You can use your existing DSL modem as just a modem, set it up as some sort of bridge-only device with no routing, then connect whatever router you want (AirPort Extreme Base Station or whatever) and use that instead. (Just a tip: for DSL, you'll usually need to configure PPoE or something similar on the router if you're using the modem as a bridge only. You or they did this on the modem/router initially but may not remember, but since this function won't be used anymore, something else will have to do it.)
It would be more helpful to know why you're looking to change. For example, if you're happy with everything but just want more Ethernet ports, a switch will do you well, cost less, and be much simpler to set up (since you don't really have to).
If you insist on changing, you'll need, at least, a DSL modem that is compatible with your ISP (check with them), and, if you wish to avoid sometimes-problematic double NATting, the ability to use it as only a bridge (and then a router that supports PPoE, though most I know of do).
PS - If you're renting your modem from your ISP, considering buying it (or a compatible one) in any case. Assuming they charge you to rent it, you'll likely save money in the long run, so it might be a good idea for that reason. Qwest (now CenturyLink) allows me to do this where I live and publishes a list of compatible modems, but lots of people rent one from them for $5/month instead since that's the default. I've already recovered the cost of buying it.