Win 7 LUA and SRP?

First, sorry if this is the wrong forum. I'm unsure of where else to ask this question!

Several months ago I built myself a new machine running Windows 7 Professional (RTM). One of the things about Win7 that I liked, from what I had been hearing at the time, was that it was no longer set up to run the primary user account as admin by default. So, naively I accepted this to be true without thinking and ran through the setup process back then without a second thought. Fast forward to today, when I'm thinking about setting up a Software Restriction Policy to keep out the baddies - and I find out that my account is listed as Administrative.

I'm a little confused about that, to be honest. I certainly still have to deal with the UAC (it's set to the highest level), and on several occasions the programs I run need to be 'run as Administrator' - But I gather that my account is still the Admin regardless of this fact.

The bigger questions I have are as follows: 1. Can I 'demote' my current account to a Limited User Account and keep all my settings, files, and programs running as they normally do? As I said, a few programs that I run extremely frequently (Process Explorer, EVGA precision, RealTemp) require 'run as Administrator'. If I can demote my account will this make a gigantic hassle for me? Will all my programs still be able to run, and write files where and when they need to? I keep logs from Chat programs, and several games and programs (A/V suites) I run update themselves automatically. Will they have the privileges they need to install and update, or will they fail to patch if I demote my account? I know for a fact that Steam hates being run as Administrator (it makes it think it's in compatibility mode, and gives an error), so I'm not sure if I'll be able to update/download games with a LUA.

And, 2. Can I set up a Software Restriction Policy on Windows 7 Professional? I missed the boat with XP, and apparently now Microsoft took the SRP capacity of Windows and shoved it into a new feature called Applocker - which is not available on Professional. Will I have to upgrade to Windows 7 Ultimate if I want SRP functionality?

So, I guess I'm confused about Admin accounts, LUAs, and SRP on Win 7. I'm mostly curious if I'm going to completely bork my machine trying to tighten security and pushing down the privileges of my user account. Sorry for the long, rambling question, but thanks for any help.