I'll consider a shared hosting in the start. The reason is, if you subscribe in any cPanel host then when you will have that kind of boost you can quickly move to a personal server within 30 minutes in some case!
Well if you need 7/10 GB space I guess you should start with a VPS. But VPS has the hazard of some short of management.
Make: Dell PowerEdge 2650
Processors: DUAL Intel Xeon 2.8GHz, 512K Cache
Technology: HyperThreading, 533MHz Front Side Bus
Memory: 6.0GB DDR at 266MHz Frequency
Redundant AC Power: 2x500 Watt Power Supplies
Hard Drives: 5x146GB 10K RPM Ultra 320 SCSI
Total Capacity: 730GB working redundant via RAID5
Networking: Intel Pro 1000MT Dual Port Gigabit
That is correct and server configuration have very little effect in shared hosting market. It totally depend how many accounts they have on the server and you share with everyone else. Good servers costs more so companies usually put more accounts on the good spec machines.
Its a better idea to mail sales asking about details like is there any limit of users they put on each server and if they over sell or not things like that.
There is no such thing as unlimited space/bandwidth. They simply are expecting that you will go with them since its unlimited, but only use very little space/bandwidth. But these hosts oversell very drasticly, so you should avoid them.
I'd recommend the $44.50/month cPanel VPS from PowerVPS. They're great, and have great support.
Stay away from GoDaddy. They offer a lot, but its because they oversell a ton. Just search for them here, and read the reviews, and that'll surely change your mind about them.