IME, the first style is called camelCase, and the second PascalCase. Note that
this Wikipedia article, however, says they are both camel case and should be called lowerCamelCase or UpperCamelCase (edit: that used to say UpperPascalCase, which is wrong...oops). I say I've never heard of such terms - but do realize that wiki engines in general call PascalCase camelCase.
I submit the
.NET Framework Design Guidelines on Capitalization in my defense.
For .NET, Microsoft has the above design guideline for the BCL. I'm sure Java has something similar. It's probably advisable to follow those guidelines, so here's the relevant portions of the .NET one:
a. camelCase for parameters, local and (non public) member variables
b. PascalCase for classes, enum types and values, properties, functions, events, readonly statics, public member variables, interfaces, namespaces, and acronyms more than 2 letters long
c. no
Hungarian notation
d. no prefix for member variables (I'm not entirely sure this is in there, I know it recommends against underscores for
class names, but others have stated it does as well for member variables. I do know, however, that you cannot be
CLS compliant with an underscore prefix)
And, now that I have given the "official" recommendation, here's how I actually do it for both VB.NET and C#:
a. camelCase for local variables and parameters
b. PascalCase for pretty much everything else
c. _camelCase (camelCase with a leading underscore) for private or protected member variables
d. ALL_CAPS_WITH_UNDERSCORE for constants
e. Hungarian notation only for web or WinForm control variables
IOW, it's a strange mix of .NET guidelines and my own peculiariaties. Oh well, at least I'm consistent.