Both GBrowse 1.7 and 2.0 support NGS data visualization, see tutorial here and poster here, but several improvements had been made for GBrowse 2 such as updating image via AJAX.JBrowse as the next-generation of GBrowse which is implemented by javascript will certainly bring even faster and smoother experience for users. We have integrated it in our project, and it looks very fancy and portable. It supports viewing NGS data as well, see here, however, as far as I know, it's still under development, and there are bugs yet to fix. You may also consider Dalliance.

Jbrowse is pretty interesting. It looks like an intuitive, responsive and fluid online genome browser to use.

Last time this question came up I mentioned WebGBrowse, which could be really handy to set up quick demos I think--but may be lighter than you need. But I forgot to mention Gaggle Genome Browser too.

I did a longer post on that here, Gaggle is a set of things that can work together that might have other appeal too.

In my bookmarks:

• Lookseq: http://www.sanger.ac.uk/resources/software/lookseq/
• AnnoJ http://www.annoj.org/

• see also: Next Generation Read Sequence Assembly Visualization Software

New browser: I'm just starting to look into this, haven't gotten very far--but GenPlay has just been published recently:

Publication: GenPlay, a multi-purpose genome analyzer and browser

GenPlay site: http://genplay.einstein.yu.edu/wiki/index.php/About_GenPlay

For a light weight solution, try genoverse.