Internet pc build

Hello guys and gals,

I feel like a total noob here but the only stupid questions is the one not asked...

I have an old (2003) Acer Travelmate 802 XP Pro (never again, housing been replaced 3 times and again completely toast/cracked/hinges gone, never dropped/bumped) with a 1.3 pentium and 2 gig ram and basically unused for the last 2 years.

A Dell Lattitude D820 XP Pro (2006)1.6 with 4 gig ram.

Secretary has a desktop with 3.something Intel XP Pro with 2 gig ram.

The desktop is notably faster then the laptops at rendering Internet pages.

99% of my personal PC time is spend internet surfing gizmodo, autoblog etc with Opera and 25 tabs at a time (or more) and otherwise streaming tv shows on IE8.

Now, what is the MINIMUM recommended hardware spec for the best experience as per above use case?

1 - Value for money specs: ?
2 - Ultimate specs: ?

Please do not say Atom is fine etc because I tried that a year ago on a borrowed Compaq netbook and it was horrible.

Appreciate all feedback.

This would be good -

CPU - AMD Athlon II X2(2-Cores) or X3(3-Cores) or X4(4-Cores)
3 and 4 Cores would be better for multitasking...

Mobo - Any good mobo with 785G or 880G chipset

RAM - 2x 2GB DDR3

CASE & PSU - A standard case and a 350~400W high quality PSU from Seasonic/ Antec/ Corsair/ Silverstone

HDD - The Samsung F3s are good...

From where will you be buying the parts?

^ Why not buy it in the US ? But the above build wont cost much even in India...