If you're not gaming much than an HD4290 is one of the best IGPU solutions, especially if it doesn't stress out your current games. If you do want a good card, an HD6850 will carry you for a long time, and if you get into demanding games, crossfire them.
Hi, and no worries about all the questions. They're good and relevant!
I'd say you'll notice an improvement from updating your graphics card. What you're using now is functional at best. If you want to watch Bluray or something like that, you'll something with more grunt.
Indeed. If you're looking for just general ways to improve your system in Windows, then you should think about adding more RAM.
For anything gaming or media related, I'd get a decent graphics card. The 5670 mentioned above is very good, but for your needs also consider a 4670, GT 240 or really maybe even an 8600 GT 512mb. That would probably give you a cheap, noticeable performance boost.
So between HD5670 and HD6850,i am thinking of going for HD5670
Hope it wll last for my general needs for the next 2 years. (I repeat that i have no plans to game as such)
Also planning to wait till 2011 Q1 for ssd, then go for OCZ vertex 2 or crucial C300
And regarding an increment in RAM,will it be a boost as such? Isn't 4gb sufficient and going for another 4gb an overkill. As far as i know there is no way any ordinary user can exhaust 4gb easily unless doing photoshop or video encoding. Please clarify on this regard.