Docs Online Viewer is a free Chrome extension which uses third-party services (Google Documents api etc) to view common documents within Chrome, no other plugin/ extension required.
Supported file formats are DOC, DOCX, XLS, XLSX, PPT, PPTX, PDF, PAGES, AI, PSD, TIFF, DXF, SVG, EPS, PS, TTF, XPS, RTF, ODT, SXW, SSV, SXC, ODS, SXI, ODP, WPD.
Browse the web as usual and you should find links to supported documents have a small icon next to them.
Click the icon and it opens in Google Docs, or whatever other viewer the extension is using.
You can alternatively treat the link exactly as you did before, left-clicking it to open the file with a local viewer or some other extension, or right-clicking to save it.
If the extension is still too intrusive, you can customise it to work only with particular file types, leaving everything else untouched.