I have to agree with Pandalet.
My two favourite trips were
1) Cape Town to Port Elizabeth along the coast (stopping along the way naturally), with a little side trip to Shamwari Game Reserve. (R44 ~ 14hrs flying incl. side trips)
2) Johannesburg to a lodge on the Zambezi River via Makgadikgadi Salt Pans, Chobe, Vic Falls (Zambian Side) (B407 ~22hrs flying total, incl. Trip towards the source of the Zambezi) - A Logistical Exercise as much as anything!
All low level of course, to take in scenery and game!
Other nice (shorter) trips in SA include Wine Routes and Hermanus in the Cape, and going up the west coast.
Although any vacation flying going to multiple Hotel/Lodge/Chateau's in a Helicopter is great fun, though I can't think of anything as rewarding as bush flying in Africa.
Great Self fly hire attitude in South Africa if you invest in the right relationships, good pricing and very reasonable to do from the UK.
The "technical" trips like London (and LHR if you can fit it in) and NY Heli Routes (probaby LA too), or Mountain flying in NZ are also neat experiences.