Hi, can any one tell me which is best software available in the market for website development.I mean best.?

Also, plz mention which background would it run with if any.

Dreamweaver, hands down.
Not terribly difficult to learn, but will handle every need as you go on, including all other Macromedia products too. Not cheap, but its the best, and industry standard.

Not sure what you mean by background ....
runs on windows, dunno if mac

Dreamweaver. It's the industry standard and, at it's basic level, easy to use.

Microsoft Frontpage is pretty good. That's what I use. It's easy to understand.

dreamweaver

basically all macromedia products

Best is a relative term in this instance. Many who will answer here will answer based on opinion not cold facts.

Frontpage = easy to jump into, low cost, and very capable.
Dreamweaver = higher learning curve (for most), higher cost, but does offer some unique features and a customizable interface.
Both can be switched to split views or pure code and both have their quirks.

Photoshop = my choice for many reasons to numerous to mention...but bottom line is preference.
Fireworks = a very solid program and preferred by some.
Both can slice and gen code, and both can be used to manually output items.

I have used all extensively over 7 years and 100+ sites. They are just tools, it's what you can do with each that is important.

Dreamweaver