Most people try fitting their design to the width of a standard window size to avoid horizontal scrolling. Nielsen even claims that “users hate horizontal scrolling” , and names reasons to stray away from horizontal scrolling. But then, there are those–I dare say most of them are designers–who do it anyway. So are these guys designing without regard to the usability of their sites, do they just not give a fudge about usability, or are they designing for a situation they feel warrants horizontal scrolling?

Click this link for a showcase of horizontal sites The Horizontal Way

I cringe when I see a sleek interface coupled with a default scrollbar. The problem being, that the design either clashes with or is stifled by the default scrollbar. However, there are definitely challenges in implementing custom scrollbars both in their visual design as well as their functionality and implementation. It’s a tough call. If you think we should stick with our old pal the default scrollbar vote this trend up, but if you think we should step up to the plate with custom scrollbars vote this trend down.

The default scrollbar sticks out like a sore thumb and gets in the way of the overall hierarchy on the page:

Although this design has a sleek presence, it may almost be too subtle lacking standard elements such as up/down arrows. The other downfall of this particular site is that it is all flash making it less searchable:

References and further reading:
Custom DHTML Scrollbar Tutorial
Cross Browser and Standards Compliant Custom ScrollBar Script by Hesido
Scrolling and Scrollbars by Jakob Nielson
evernote.com
dimellashaffer.com