Hi there gentlemen.
I have some information regarding ArcGIS 10 and an explanation for you regarding the problem described in this post. If you are trying to run Sample on raster datasets in GRID format, the resulting fields will have the names you expect. i.e. the name of the raster. However, if you use non-ESRI GRID, then you get the weird names like G_G_G7 or similar. Prior to ArcGIS 10, all input rasters are converted to GRID for Spatial Analyst functions. So, for example, one of your inputs was "my_really_long_name_dataset.img"; we will convert that to a GRID, but GRID's have a name length limitation. While in the background it is named G_G_G7 and that becomes the resulting field name in my example.
Now, in ArcGIS 10, we natively process that IMG (and all other formats) limiting the conversions and scratch files that would normally be created. A byproduct of this, and in fact an influence on the design was that Sample now returns the field names users are expecting. There are some caveats, such as output to .dbf which has field name length limitations (not created by ESRI). If you're migrating to ArcGIS 10, I would also like to inform you about a new tool. It is called Extract Multi Values to Points. This new tool is further enhanced by giving the user the option to specifically name the output field. So if you have "my_really_long_name_dataset.img" and don't want that to be the output field name (in a geodatabase of course), you can name it something more meaningful to you.
ArcGIS 10 will be available this week. I hope this information is helpful!
Best Regards,