If you are a developer then you want a reseller shared hosting package from a reputable web host who will offer you support. You don't want to get your own dedicated or VPS box that you will have to be the sysadmin for.
Development is fairly predictable work, sysadminning can be all-out chaos. With development you are dealing with stuff you know and have chosen to work with. With sysadminning you will be dealing with whatever the problem of the moment happens to be. You'll have to deal with system configurations, spammers, DoS attackers, email delivery issues and who knows what else. If you won't want to have to be available 24/7 to solve problems that you may have no expertise in, then get a well supported reseller shared package and stay away from dedicated, VPS, or cloud servers.
Now, having said that, if your clients are heavy enterprise level sites, then you're not going to be able to get away with shared hosting so you'll have to look at dedis or VPSes or cloud servers, but my experience has been that small shops like yours don't typically have that enterprise-level requirement.
I've seen a lot of web designers and developers go down the tubes because they embarked on this same step and grossly underestimated the amount of knowledge and work required to maintain a system. It's easy to think that maintaining a web server isn't hard work when someone else is doing it for you and you have no visibility into what they're doing. That's why I very strongly recommend that you source out and be willing to pay for very good sysadmin support. Over time you may become knowledgeable enough to sysadmin your own system and you can drop that level of support at that time.