This question is being posed by Mazlyar Saleem at The Ridge Wired in Singapore. Read his article and then the decision is yours.
New OS? Vista Service Pack?
Starting off the article is a very nice piece of Windows glass!

Microsoft released the first public beta of Windows 7 to the general public in early January. I can tell you upfront that if you’re already a fan of Vista, you’ll actually love it even more. Even if you don’t really like Vista that much, take heart because the makers of Windows 7 have re-evaluated pretty much everything about Vista, and made changes small and large across the board. This results in a better Windows, no matter which way you look at it.
The first thing you will notice is the new interface. There is a whole lot of glass, even more than Vista, and the taskbar is much more translucent. You’ll also notice that the sidebar that was quite a nuisance is also gone. Similar to Vista though, you can still add gadgets to your desktop and position them to your liking. The gadgets are slightly less of a performance hog, but not much else has really changed.
The most noticeable thing though is the new Taskbar. Somewhat akin to the Mac OS X Dock, the taskbar now has huge icons that serve as shortcuts to open programs and also show currently opened programs. You can also move the icons around, which is quite useful. In Vista, we saw thumbnail-size previews of windows when the mouse was hovered over an application in the Taskbar; but you could only really see one preview at a time. In Windows 7, thumbnails for multiple windows appear onscreen simultaneously, arranged side-by-side in a translucent strip. Hovering over a specific thumbnail brings up a full-size preview of the window, and windows can also be closed directly from the thumbnails. You can also middle-click the taskbar icon to open new windows or middle-click the thumbnails to close windows.
The system tray, with its myriad of notifications, and the plethora of icons taking up precious space on the taskbar, has always been a source of great irritation to users. Windows 7 finally brings us some tools to help manage the mess. For each application, you can configure individually whether or not to display its icon and its notifications. The overflow area (where the hidden icons go) hasn’t changed much, but now pops up instead of extending the system tray – which is an improvement in my opinion. You can also move around icons in the system tray now just like the taskbar.
At the far right of the new Taskbar is a little rectangle of what looks like unused space. Hovering your mouse over it activates a feature called AeroPeek, which makes all your windows transparent, allowing you to see your desktop behind them. This is especially useful for viewing your on-screen gadgets. Clicking the rectangle acts like the old ‘Show Desktop’ button, minimising all your windows when clicked on once, and then restoring them when you click again.
Another new feature called Aero Snap allows you to dock windows by dragging them to screen edges. So dragging to the left or right edges maximises a window to half the screen on that side, and dragging to the top maximises it to the whole screen. Shaking a window will cause all other windows to get minimised, and doing it again will cause them to come back up.
A new feature to help you work more efficiently is Jump Lists. This adds a handy submenu to many applications, so you can see items that you recently worked with in a given app, or look at further options you have for starting new documents or accessing often-used features. This works both for items in the taskbar, and those pinned to the start menu. The immensely annoying User Account Control has also been revised, and now includes 4 levels that the user can specify – making it a bit more tolerable.
The biggest question on everyone’s mind though is whether Windows 7 introduces the much-needed performance improvements over Vista. Although I haven’t been able to run any actual tests yet, preliminary usage would suggest that there is definitely an improvement. Throughout the OS, windows open faster, apps seem to launch more quickly, and the overall interface seems snappier than it was with my Vista installation on the same machine. Start up and shutdown times seem to be quicker too. However, in terms of actual usage, Windows 7 is fairly unexceptional in the sense that while it has some nice improvements over Windows Vista, none of them are particularly major changes.