Card(s) for dual monitors...(to be upgraded later)

Initally, I had no inclination towards dual monitor setup until I saw a friend using it and it made great sense to be able to do things across dual monitors - though my only interest is not just for dual screen gaming, but multi-tasking (video editing, gaming, netflix, etc) across dual monitors.

Unfortunately, I cannot afford another monitor at this time.
However, since I want to be able to use dual monitors later, I dont want to get struck with a card which cannot be tag-teamed later for optimal setting :-)

What is the best route to approach this scenario...which is bascially...
get a not expensive card now to be able to do stuff decently,
later when I can afford it, get another card and the addtional monitor to attain the optimal setting

What are the best set of cards for this scenario?

Thanks

ATI Radeon HD 5870 eyevinity
for setup here : http://www.amd.com/us/products/tec [...] inity.aspx

yes.. ! and you need VGA splitter or adapter dvi to pc
http://www.highdisplay.com/two-monitors-one-computer/

like this ..?

JUST ADAPTER

VGA SPLITTER

Dual monitor different software in 1 PC

Interesting....

question mate.. does this mean that Eyefinity setup too need this sort of adapter?

okay... so it doesn't matter which modern graphics card you get, they all support dual monitor setup for both clone, Span or extended modes (not interested in the Hybrid Span mode).

So this setup works I guess,
for now -- monitor (1), 1 graphics card
for later -- monitor (2), to do dual monitor thingy

Now.. onto the future proofing part...

1. on nvidia site it says "All displays must have a common resolution, refresh rate, and sync polarity" -- does this sort of restriction apply to ati as well? (for regular non-3D monitors)
2. ( as the current trend ) if I get a 3D monitor for monitor (2), would any graphics card(s) support dual monitor setup, i.e., regular, 3D ?