To add to what Ann said, the nearest bus on the north side of the hill is the 63/363. The 63 runs from Old Camberwell Cemetry to Kings Cross via Elephant & Castle/Blackfriars. The 363 starts at Crystal Palace and runs to Elephant. This is probably the route I use most often and there is rarely more than 10 minutes between buses, often less.

If you walk to London Road, which is about 10 minutes from any part of the hill (via Horniman Gardens from the north side) you have the choice of a 185 to Victoria via Oval or a 176 via Waterloo Bridge towards Charing Cross.

There are also the 'small' buses, the P12 to Surrey Quays and the P4 to Brixton. The Transport for London website can show you exact routes:

http://www.tfl.gov.uk/tfl/gettingaround/maps/buses/

I have lived near Canonbie for about 25 years and can't really fault it. It IS a steep hill so if that is likely to cause a problem then avoid it. However, the hill and the views to London (or the south) are also a major plus and make you feel like you are well away from London whilst still very close.

Highgate is simply the Forest Hill of the north in my book!