I would suggest starting out with one of the VPS hosting solutions. If you are already worried about server resources, this would be your best bet for a middle ground-type hosting platform that still has a lot of the friendliness of shared hosting, with some of the more advanced limitations of a dedicated hosting plan. Might also e-mail in all your requirements to
sales@lunarpages.com and allow our sales team to look over your needs to see which hosting plan would be best for you.
Please come back and let us know how it goes!