depends on server and db load (aka visitor count). Start with shared hosting but have a plan in place to seamlessly migrate to a dedicated environment as your server load starts hitting the limits. I've been impressed with hostgator's support and response. Totally fanatical.
Have absolutely wonderful experience with the following since last 4 years either for my own needs or while dealing for client sites
All of the above provide ability to host unlimited domains from single account & 24x7 live chat support. Uptime is 99.9999%
there're plenty but the above ones are some of the most popular ones and suit your needs.
2 Votes for Hostgator.
Thanks for the suggestion
Vijay Bhatt said:
we have hosted www.maangal.com on hostgator.com and havent had any issues so far and they have a lot of solutions for all businesses. you could also try exabyte.com , we did some business with them and found them to be quite good.