For a portable document format the Acrobat 4.0 PDF reader is available as a free download for many operating systems, including Linux, although there is no sign of a free PDF writer as yet. Personal finance is becoming dominated by Intuit's Quicken, and there is no sign of a version for Linux yet - but GnuCash is another free download, and it can import Quicken files. The Gimp image manipulation program emulates and in some instances beats PhotoShop. And it is free. On the hardware front printers and scanners now mostly work with Linux, although it is wise to check the Linux hardware compatibility list before buying.
Modems are still a sticking point.
The trend in modem manufacture is to allow some of the processing to be handled by the host processor. For Linux advocates this is a bad idea, because such 'WinModems' are incompatible with the Linux drivers, and manufacturers are reluctant to release the specifications needed to write new drivers. Even so there is a way round the problem. Windows refuses to recognise a Linux partition, but Linux comes with read and write drivers for the Windows file system, so the computer can then be restarted into Linux, which can read the downloaded files from the Windows system. This is annoying, but it works.