I want to know the REAL difference between Windows 7 Home Premium and Professional/Utimate.

In India, the cost of different versions:

Ultimate - 11,200 INR
Professional - 10,700 INR
Home Premium - 6,600 INR

The absolute cost of the first two is so high to me that the difference (500 INR) doesn't matter. So to me there is really no choice between the first two - If I decide to buy the Professional version, I'd rather go for Ultimate itself.

What I want to know is, whether Home Premium is enough for my needs.

I tried searching for comparison but many look like just marketing junk from MS. They are short and vague. According to this page, the major differences between Pro and HomePremium are

1. Run many Windows XP productivity programs in Windows XP Mode.
2. Connect to company networks easily and more securely with Domain Join.

You can do both in Pro but not in Home Premium.

I intend to use my Windows 7 for a small business - just starting up. So I'll be dealing with the following:

• All kinds of development tools, servers
• Very important - I will run Virtual Machine Software (MS VPC or VMWare or Sun VirtualBox etc..)
• My system will be acting as the server for most purposes till I can afford dedicated servers.
• Connect the system to a variety of network devices (PCs, Printers, etc..)
• Run productivity, business and financial apps
• Any other small software startup business requirement that I haven't thought of yet.

Professional (and Ultimate) is twice as expensive as Home Premium. So it'd be great if someone can point out the things you cannot do with Home Premium, when you use it like I explained above, so that I can make a decision about which one to buy. I need some real-life experiences so that I can make an informed decision - not a decision based on marketing junk.