I'm also looking for a site like this(though I think everyone is); but if it helps, here are some sites you SHOULDN'T go to. The ones I heard about, I heard about through yahoo answers or reddit threads.
Mangad*ep- Has malware ads, but aren't very obtrusive. Probably best bet so far; thanks kingpipot89!
Mangap*nda- has instant redirects and pop-ups. For me it was completely unusable.
Mangastre*m- heard it has exactly the same problems as Mangap*nda.
Mangare*der- has same problems as aforementioned sites.
Mangah*re- heard it has malware ads and redirects.
Mang*go- has malware ads and redirects.
Kis*manga- has alware ads and horrible navigation that causes you to click them unintentionally. Also redirects.
Mangaf*x- Has malware ads and pop-ups.
Onem*nga- heard it has malware ads and redirects.
Mangap*rk- obtrusive malware ads.
Thespe*trum- has malware ads and redirects.
I'm updating this as I find or remember more sites. Also, most of these sites are still usable with the proper ad-blocks, I personally would just rather stay away from sites that try to give you viruses( or affiliate with ad companies who do the same).
Mangastream is legit, they're scanlators and share their own scanlations in high resolution. I feel it ought not to be on that list.
On another concern, I feel that if some have in their bookmarks quality sites with quality contents, they will not want to share it in public, for fear these sites will eventually crumble under leechbot traffic and die from DMCAs.