I started a new project called plotmoi, hosted by code.google: http://code.google.com/p/plotmoi/. The goal is to plot any formated or non formated data. After some hours of coding plotmoi can generate interesting svg without pain. For example, I extracted from a database the following table in tests/reallife_data_5.data:

   size   | count 
 ---------+-------
        1 | 73719
       17 | 58136
       21 | 51949
       19 | 47431
       16 | 47027
       15 | 46303
       24 | 44450
       25 | 44388
 ...
 (25673 rows)

Then run plotmoi:

$ python src/plotmoi.py tests/reallife_data_5.data plotmoi_loglog_example.svg

It generated this svg file (log/log scale). bitmap preview:

You can retrieve sources via subversion:

svn checkout http://plotmoi.googlecode.com/svn/trunk/ plotmoi