BTW, if you're paying for a very high-speed package, it's worth remembering that your actual experience will be limited by the slowest device standing between you and the internet.
In the case of a wired connection, things to look out for include the port speed on the router, the port speed on the switch/hub (if you've installed one) and the speed of your network adapter, and in exceptional cases the speed rating of the cables you're using to connect everything together (though most modern Ethernet standards support up to gigabit speeds)
So for example if you're paying for a 200Mbps package, then the hub has to support 200Mbps+ speeds (it's likely to be 1 gigabit as the speed typically jumps in powers of ten), but so does the switch (if it's a 100Mbps switch you won't get more than 100Mbps out of your connection, no matter what) and none of that will do you much good if you're using an older computer with a network card limited to 100Mbps. You might also find that some older switches are half-duplex, which means that they effectively have to reserve 50% of the bandwidth for traffic in each direction, so if it's a 100Mbps switch you won't see speeds above 50Mbps from it.
In the case of a wireless connection, then key factors are the router, the max speed of the wireless standard being used (a/b/g/n etc.) and the max speed of the wireless card. That gives you an absolute best case scenario i.e. if you had the wifi router and the card a few inches apart and there were no other wifi signals or anything else causing interference, you might expect to get close to the rated speed. But then the numbers start to be eroded as the distance to be spanned increases, obstacles get in the way, and the wifi channels hit contention issues (caused by neighbouring wifi networks) or suffer from interference (basically anything electrical could potentially cause problems; some regular culprits are speaker systems, microwave ovens, etc.)
You may also find that your provider's bundled modem/router is pretty rubbish at wifi, but does a perfectly good job of providing a wired connection. In which case it might be worth investing in a separate wifi router, and switching your ISP supplied device to modem-only mode.
It's too big a topic to go into more detail here, but hopefully that gives you a few pointers to think about.
