The Society of Biblical Literature, in association with Logos Bible Software, has made a critically edited Greek New Testament available free to download. It's things like this that cheer a biblenerd up! The Greek New Testament: SBL Edition (SBLGNT), which is freely available in electronic form and for purchase as a print edition.
I'm all about ease of use and making my research simpler so when they use phrases such as "both students, teachers, clergy, and interested laypersons can use the SBLGNT in their study and writings without having to input the Greek text letter by letter" I'm hooked :) I've just downloaded it so I haven't tested it out entirely but I will keep you posted. Have a look at the fatastic BetterBible blog for more detailed info.
And for those of you who have been living under a non-biblical rock, check out the SBL Greek Font.