We've come to depend on home internet access as much as (or maybe more than) we used to depend on our land lines. If you've got dead patches in your house or, worse, slow or patchy connectivity, you may be able to fix up your network with an afternoon's worth of mild effort and experimentation. If you're willing to lay down some cash, you can make your network even sweeter. Here's how:
Move your router. If you've got dead patches with no wireless connectivity, you may just need to move your router. Make sure that it's as open as can be, and up high if you want to reach the next floor up easily. If your house is large, has many walls, or has funky materials that shield signals, you may just have to buy an extender of some sort (see below), but first you should tinker with placement until you've got the broadest coverage possible.
Replace your cordless phone. This may not be a problem for you, but some older cordless phones can cause major interference with the once-ubiquitous 2.4GHz wireless band. Try switching channels, if possible, then consider a new land line. The interference can potentially come from many other sources, though, including cell phones and neighboring networks, so if you live in an apartment building or somewhere else with densely overlapping wireless signals, you should consider getting a new router (see below).
Use a signal extender. This is a cheap alternative for folks who live in large houses (or work in large offices, for that matter). If walls or other features keep one router from filling your space with bandwidth, pick up a cheap wireless extender or two and set them up strategically. They are typically quite simple to install and require little maintenance, and are likely the best answer for large spaces.
Use a plug-in (power line) extender. This isn't technically a way to extend your wireless network, but it can work wonders in certain situations. The idea is simple: Just plug a networked device into a wall outlet and pick up a signal from any other outlet in your house. I use a power line extender to extend my network into my garage after many fruitless attempts at stringing my wireless that far, through that many walls. Some older houses may not be friendly to this setup, so try before you buy, if possible.
Get a new router. Has it come to this? If your router is more than a few years old, the odds are that it's time for a new one anyway. The 802.11n standard can make a world of difference in both speed and range--presuming your networked devices can recognize the signal. Any laptops and other devices that came out in the past few years ought to have 802.11n baked in, but you should check to avoid some serious disappointment. Many routers include signals that can work with older devices, so know what you need and shop around.
Whether you spend an afternoon moving your old router around or drop a couple of hundred bucks on new hardware, you should be able to work up a solution that keeps you and your people happy. It's well worth it; any investment you make in your home network should pay off in reduced stress over the coming months and years.