<p>While working on a .Net application (let's say an Asp.Net one), are there any differences in the way you would do things while working on the 64 bit platform, as compared to working on a 32 bit platform.</p>

<p>I would imagine very little since you are working on the framework, and the framework is taking care of most things for you, right?</p>

<p>But, please give your comments.</p>

<p>Thanks.</p>

There are two cases where considering 64-bit-ness might be interesting:
you need to consider containers that have more than 2^31 elements. The standard array .Length property returns Int32, and is thus not capable of representing large arrays - which you can't create in a 32-bit VM anyway. In a 64-bit VM, you should use LongLength instead (unless you know that you have less than 2^31 elements). Unfortunately, many standard collection classes don't seem to support large numbers of elements at all.
you can use the long type with fewer concerns about performance: in the 64-bit version, a long fits into a register, whereas in the 32-bit version, the JIT code will need multiple machine instructions for a single long operation.