Well, I think beer can be greatly altered/improved by the way it is served. For example, flat lager tastes absolutely awful because there is no bite from the carbonic acid to offset the neutral flavours of the lager. Similarly, an ale taste much better with low carbonation as it allows the fruity flavours to come through. Ale served through a beer engine is even better, but that's something you can think about once (if) you start kegging.
The plastic barrel is a good cheap way to start. The first time I used a barrel (a £20 'economy barrel') I thought my beer tasted 10X better. It's easy to use, just rack your beer into the barrel after fermentation, add a small amount of sugar and wait a few weeks for it to mature. After that, the natural pressure will allow you to draw about half of the beer out (the safety valve will keep the beer at standard ale carbonation). Then, you may need to buy a S30 'Hambleton Bard' CO2 bulb from your LHBS, which from memory are around a tenner, and a fiver to refill. A few squirts at the start of a drinking session will allow you to draw off a few pints. The big advantage is only having to sanitise a keg rather than 40 odd bottles, plus I swear ale tastes better from it. I would resist the temptation to invest in the more expensive 'King Kegs', I have personally had trouble with seals on them, which seems to be common with the newer ones.
If you're brewing lager, or highly carbonated Belgian beers for example, then Cornelius kegs are the way to go. There are plenty of threads to search on Cornie kegs along with Daab's pages so I won't get into it here, except from saying I have about 8 cornie kegs now and I swear by them
