One of my current providers offers a pretty unbeatable deal. I won't list all the features but here's a few that had me sold:

• 300gb triffic
• Unlimited domains
• 2500 email addresses
• All for around US$7 per month

Pretty hard to beat. So lets take a look at the green hosting solutions on offer.
It's encouraging to see that there are a growing number of web hosting services who are turning green in an effort to service those of us with a social and environmental conscience. Here's my list of top 10 green website hosting companies:

1. Dreamhost
Location: US
Energy Type: Renewable Energy Certificates (Solar, Hydro, Wind Etc)
Prices: from US$7.95 per month
Features include:

• Unlimited domains
• 148 GB traffic per month
• 3000 email accounts and a heap of other features.
• MySQL Databases (unlimited)
• 24 hour email technical support
• Up to 75 FTP users

2. Green Hosting
Location: Canada
Energy Type: Wind
Prices: from $39 per month
Features:

• 5 MB of server space (extra capacity is available at additional cost)
• unlimited data transfer (also called 'unlimited bandwidth' or 'unlimited hits')
• 5 POP3 vanity email accounts (more available at additional cost)
• unlimited email forwarding
• unlimited email aliases
• web statistics
• Windows or LINUX based hosting

3. Think Host
Location: US
Energy Type: Wind & Solar
Prices: from $5.95 per month
Features:

• 40 GB storage
• 200 GB bandwidth
• MySQL DB
• Multiple Domain capable
• 25 Email accounts
• Web mail client

4. Sustainable Websites
Location: US
Energy Type: Wind
Prices: From $10 per month
Features:

• 1 GB storage
• 10 GB bandwidth
• 25 POP email accounts
• MySQL DB
• 5 add on domains available
• Web Stats

5. ASIO
Location: US
Energy Type: Solar
Prices: from $9.95 per month
Features:

• 250 MB storage
• 5 GB bandwidth
• 250 email accounts
• Linux / Windows hosting
• Spam filtering
• 99.% uptime guarantee

If you're going to be hosting multiple domains then Dreamhost seems to be the best value for money. The details above don't really do them justice as they their green hosting accounts have a huge array of features.