I agree with PTim, absolutely, start at the begining without COM or TLF. As a teenybopper I tried to read Soul Music, got confused but already knew I loved Death, Susan et al, and went back and started with Mort - best decision for me by far. Hooked!
Some of my friends however, have jumped into DW via Tiffany & Co., so I wholeheartedly recommend that route too. It's certainly wise to consider the person you're making the recommendation for! If they love comedy and fun, then there's nobody better than the Nac Mac Feegle. However, if their humour is more on the dry side and they love a good parody with a bit of a pinch, then the Equal Rites or Mort route is a sure winner.
I'd love to be starting off again. I envy my yet-unaware friends sometimes, does anyone else ever feel like that??
"As full of hustle, bustle and sheer exuberant busyness as a dead dog on a termite mound." [Mort]