Me personally, I like this with the suit... But since we don't know you, it's kinda hard to recommend a hat, go try some on and see what looks best on you. Some people can pull off hats, some can't. Also, get in the habit of putting sunscreen on your dome everyday. Put it on your face while you're at it too... look for a facial sunscreen that's oil free. I'll step off my skin care soap box now.
How certain types of hats will fit you truly depends on a lot of factors, including the size and the shape of your head. Weather is also a huge factor, as different seasons will often require different styles of hats. Since you don't seem to wish to go in the retro/stylish/madmen way, perhaps a Flat cap might work for you. They can go from really light materials(for summer) to wool ( for winter) and a nice practical thing about them is that you can usually put them in a jacket pocket (or sleeve) at coatchecks. And yes, I do own one of these too.
Rainbow offers sage advice. Shape and style of hat are determined by your body size (imagine if Hoss and Little Joe switched hats on Bonanza, or if Indiana Jones wore a fedora with a shorter brim). If you're serious about it, go to a good hat shop. They'll be able to advise you and should have a block and press that can provide a more personal shaping to fedora-style hats if that's the route you go. A straw Panama hat for the summer works. Personally, I like English caps--wool tweed in the winter and lighter poplin in the summer. They're much less expensive and much easier to care for. Well made fedoras and Panamas can be pricey.
You could go with the Holden Caulfield, though you'd have to bitch about phonies all the time. Hipsters might have this market cornered. Spoiler On a more serious note, depending on where you live, I think beanies (winter hats) are a fair solution, at least during this time of year. You can go as stylish or as understated if you want. I'd say these are acceptable in a business setting. I wear one almost every day in the winter myself, and a baseball cap in the summer for times I don't feel like showering in the morning.
What better excuse to do some serious peacocking? The only inconvenience would be constant fellatio from HB 9s and 10s you just met. I personally can't stand wearing hats and will only do so in cold weather. (We're talking Chicago cold - I've never worn a hat in Los Angeles.) But most guys can rock a plain baseball cap, at least in informal settings or in transit. When I inevitably start losing my hair, my plan is to shave it and bulk up. But that's a serious sunscreen investment, particularly in California.
The beer hat is a classic and you've got a built in excuse to drink all the time. Boss: Why are you drinking beer from your hat at work? You: If I take off this hat I'll get cancer and without the beer it's highly unbalanced. You wouldn't want me to fall over and have a worker's comp claim would you?
Perhaps the metrosexual pirate look will help with sales... On a semi-serious note, if you're going to wear a hat with a suit it needs to be very apparent that it matches the suit. See my good friend and snazzy dresser Vign Rahmes. I've rocked the following to some meetings
Crocodile Dundee hat's look disturbingly natural and appropriate on me. Never the less, I can't bring myself to actually wear one in public. Baseball caps or Castro caps are I think generally the only vaguely dignified option for anyone over 17 who isn't trying for an ironic/hipster theme.
Chinese fashion celebrates the pinnacle of function taking form, bending it over the nearest waist-height object, and brutally and savagely violating its asshole over and over and over. It's a good look.
This. Spring for a proper one (you can usually find them at decent men's shops). Expect to pay $250-400 depending on what you are after. Get it to match your overcoat so in the winter, you will match. In the summer, it doesnt need to match (hats are like jackets in that they don't need to match the "street clothes" you are wearing). Pinstripes, though, may be a little risque. People might think you are here to rob the bank, or engage in a 1920's style police chase.