Advise about reporting

Hello everyone,
I'm pretty new to all this SEO. I have my own web site an am trying to decide whether to have a go at SEO my self or get a company to do it for me. I was hoping some people here could offer some advice on what to look for in reporting from SEO companies... what are good benchmarks apart from the obvious increase in rankings to show that they are doing what they should, and what kind of monthly reporting should i be asking/looking for? my initial thoughts are:
month on month changes in rankings for spacific key phrases.
month on month changed in backlinks
month on month changes in web stats
some kind of report on any social media that has been set up used

Are there any other useful things i should look for?
Hope some people can help, all suggestions welcome and thank you for your time!

Here are a few resources you can check out on the topic:

Google: What's an SEO? Does Google recommend working with them? (Read this first)
6 Tips for Choosing an SEO Company by Aaron Wall - A bit dated but helps.
How to Hire a Good SEO Expert by James Maguire - Pretty old too but contains some good gems.
How to Choose the Right SEO Vendor by randfish of SEOMoz

thanks, and appoligies for posting up the topic before doing a proper search... i did find a good thread posted last year.

I think in the short term i may well have a go my self and see what i can learn.

If you want to look at some stuff your self rather you can make use of the following Google Tools

Google Analytics
This gives you very useful information about who is using your site, which pages they looked at, what keywords they found your site for, which pages are performing etc.

Google Web Master Tools
This actually tells you where you are ranking for the keywords that people find you for.

Also, many people under estimate the power and flxability of a Spreadsheet. Openoffice.org is free and excellent! There is so much data analysis you can do if you set up a few spread sheets.