Whatever you do, don't sign any 24 months contracts, whether for your ADSL Line, or ISP. Don't be conned into signing a contract that gives you a free modem. Buy your modem upfront.
This gives you maximum flexibility. You can swap/chop/change ISPs as you like, or you can even cancel ADSL altogether if it doesn't work out for you.
Choose Telcom Closer Option 2 if you don't have a line already, as it comes with free installation, and you can cancel the "Closer" bit afterwards, and only pay normal line rental, if you don't care about voice.
I'd stay away from the Telkom Do packages, and go with an ISP like Afrihost who are actually bringing prices down, and doing alot for the consumer. You can always buy local bandwidth from any ISP quite cheaply. The free local bandwidth that comes with Telkom packages is a con. Don't get conned by it! We all want simple, cheap, afforrdable packages, without having to deal with local only traffic, or traffic splitting, and local and international accounts... So just stay away from the Telkom packages, IMO.