Well one service which i enjoy very much is Google Ngram,developed by Jon Orwant and Will Brockman of Google, and charts the yearly count of selected n-grams (letter combinations) or words and phrases, as found in over 5.2 million books digitized by Google (up to 2008).The words or phrases (or ngrams) are matched by case-sensitive spelling, comparing exact uppercase letters, and plotted on the graph if found in 40 or more books during each year (of the requested year-range).The Ngram tool was released in mid-December 2010.The word-search database was created by Google Labs, based originally on 5.2 million books, published between 1500 and 2008, containing 500 billion words in American English, British English, French, German, Spanish, Russian, Hebrew, and Chinese. A user of the Ngram tool has the option to select among the source languages for the word-search operations.Some of the interesting results which I found were:
1)Newton vs Einstein

Surprisingly,Newton has an upper hand here.

2)Adolf Hitler vs Joseph Stalin vs Benito Mussolini

Hitler eh!

3)Abraham Lincoln vs George Washington

it's neck to neck.

4) Jesus vs Sex

Red worm surely is rising.

You can do all sorts of comparison.Go ahead.