Navagon: D2D has activation limits on every title. If you're looking for DRM-free games, look elsewhere. The Steam versions use DOSbox and therefore don't need Steam to run, if that's any help.
Blarg: Thanks for the tip. I knew it had to be too good to be true.
Navagon is incorrect. There are a number of titles on Direct2Drive specifically listed as DRM free. For instance three of the five X-Com titles (including the first 2) are listed as DRM free, see links:
[url=http://www.direct2drive.com/7575/product/Buy-X-Com:-UFO-Defense-Download]http://www.direct2drive.com/7575/product/Buy-X-Com:-UFO-Defense-Download[/url]
[url=http://www.direct2drive.com/7571/product/Buy-X-Com:-Terror-From-the-Deep-Download]http://www.direct2drive.com/7571/product/Buy-X-Com:-Terror-From-the-Deep-Download[/url]
[url=http://www.direct2drive.com/7570/product/Buy-X-Com:-Apocalypse-Download]http://www.direct2drive.com/7570/product/Buy-X-Com:-Apocalypse-Download[/url]
I little while ago I wanted to buy Cogs from them as it was listed as DRM free. I contacted D2D customer support and asked them if they could specifically confirm that I could install and play the games which are listed as 'DRM Free' without connecting to their servers and this is the reply I recieved:
"That is correct! DRM free games can be installed and played offline."
I bought and downloaded Cogs and it was simply a standalone installer. Hope this helps.