A Sim card is just a micro SD card, isn't it? Unless there's some kind of DRM on there it would be simple to image it.

Not all hard drives are created equal. Newer Solid State drives are now offering 128Gbyte drives with MTBFs of 1.5 million hour such as the 2.5 inch OCZ 128GB SS HDD or a similar MTBF of the excellent Western Digital Veloci-Raptor Hard Disk Drives. The Solid State drives have no moving parts so do not suffer from electromechanical failure. They consume much less power and are considerable faster than conventional hard disk drives. A RAID 5 set using SS HDDs within a NAS barebones box configuration with Gigbit LAN using a UPS protect power supply should be pretty reliable.

For long term backup then magnetic tape (DV or DAT) or Magneto Optical (i.e Fujitsu 2.3GB MO Disk) Drive storage is probably the most secure stable method of storage and archival. I recently came across some old audio tapes in a box in the loft (nearly 25 years old) with some old ORIC programs and they loaded into the ORIC when it was fired up.

If anyone has an old DV video camera there is software available that will convert the DV video camera into a tape storage device via the IEEE 1394 port on the PC saving data blocks of approx 8 GBytes on to DV tape.

4.7Gbyte DVD-R/W disks are generally regarded as being more stable than normal stardard CD-R although for data archival although I seem to remember some companies such as Kodak used to manufacture archival CD-Rs (KODAK CD-R Gold Ultima) with a stated lifetime of 100 years. Highly doubtful but could still be useful even if the actual lifetime of the CD-R was 1/10 of this stated lifetime. There are not really any cheap shortcuts for long term archival data storage

Does anyone know the archival lifetime for Flash media such as SDHC?

Wow. Solid state drives have really come down in price. 128GB for about $430. That's pretty good.

Use a combination of backup ideas; Disks, ext. hard drive, on-line backup services

At home, I keep all my important stuff on an external hard drive as well as a flash drive.

At work, I am the network admin and all my 12 servers' OS drives are mirrored, and all data drives are running RAID5. I also have 2 backup servers in different locations for backups of my backups. All servers are running on their own UPS. If a hard drive or UPS battery fails, I get an email from the offending device and can generally fix it without having to power down.