d) dual card support is dependent on the driver. Not all games can benefit from dual cards.
e) cf/sli up front reduces your option to get another card for an upgrade. Not that I suggest you plan for that.
It will often be the case that replacing your current card with a newer gen card will offer a better upgrade path.
agreed ^ if you're investing in a video card at the ~$200 range, then it will be able to handle pretty much anything these days with 1 x monitor... and by the time it won't be able to handle your needs - it would be much wiser at that future time, to invest in whatever the latest generation ~$200 card is at the time, rather than SLI-ing your current one - with all the downfalls that come with 2 x cards (more power, more noise, less compatibility)
if you're going to use 2 x cards - best to do it from the start, if not - buy the best one you can afford now... then the best one you can afford in the future when in need of an upgrade