There are still some searches for which Google isn't too brilliant. For example, you can't search for certain special characters and you can't look for files (other than images) by filesize. However, there is a fantastic new improvement - you can now find pages by the date they were added to the Google index. This is very useful because sometimes it's hard to tell when a page was written - not all pages are like press releases and have a date on them! So, if you want to filter out old news or maybe see which pages have been recently indexed for a particular site, you can by adding the "as_qdr" parameter. Append your seach with "&as_qdr=1d" for pages found in the last 24 hours, "&as_qdr=1w" for the past week and "&as_qdr=1y" for the last year. (The 1's can be adjusted to any number and therefore length of time you like).
For example, to find new pages that have been talking about a pagerank update, you might search: http://www.google.com/search?q=pagerank+update&as_qdr=d1 or what new software has been added to a download site in the last week: http://www.google.com/search?q=site:download.omani.ac&as_qdr=w1.