I use rain water for kit/extract brewing so boil my whole volume out of necessity. Prior to boiling I had off flavours and found that my beer went flat over time, usually only a few months. This tended to be accelerated when storing the beer under ambient temperatures during the warmer parts of the year.
I know that a lot of people on here will say there is no need to boil tap water but I have heard it suggested that boiling is a good idea to remove chlorine, and if yeast can live in it then so can other organisms.
Its up to you whether you boil or not, but you won't know for sure unless you do a side by side flavour comparison with a boiled batch versus not boiled. In other words, tap water might seem fine until you one day do a full boil and discover its even better.
If you do decide to try boiling or want to get into small batch all grain, then a 19 litre big W pot for $19 is the best value.
Besides specialty grains and hops, the next thing to look at is yeast. US05 for hop forward beers along with temperature control, is a good start. Alternatively, ferment your hoppy ales during the cooler months and your ester driven beers when its warmer.
There is a range of different yeasts available to home brewers, and you may also want to try growing the yeast that is found in some commercial beer bottles.
Edit: spelling
