Looks like the other experts have summed up the use of Controllerbased wireless for you.
Cisco, Meru, Aruba, Trapeze and HP ProCurve are among some of the manufacturers for enterprise WLAN. As said with controllers, you'll get a single point of management and reporting - so you'll only have to configure SSIDs, authentication, monitoring and reporting on one node, rather than every AP.
I prefer Aruba - I've installed and administered enterprise WLANs with Cisco, Meru and HP - all good, but Aruba had some extra finishing touches in the software. But all manufactureres deliver good WiFi solutions.
The thing with Aruba (and also Cisco and Meru at least), VLANs and swithces is the following; The terminate all VLANs on the controller. So for switch configuration - put all ports connected to APs in statically assigned VLAN for AP (Management VLAN - created during setup) - and still the APs can have multiple SSIDs with multiple VLANs - as long as VLANs is configured on controller and firewall. As stated, you need a PoE switch so that you don't have to drag AC-adapters around the building.
What to consider prior to installing:
* How many users during peak hours?
- You shouldn't have more than max 25 (10) users per AP. 10 for business critical services, email, AD, database
* What services do you provide?
* how many APs and what band do you plan to deploy?
- make sure you also select 802.11n
- You'd also would benefit from doing a Site Survey prior to installation, download inSSIDer from
www.metageek.net. Mainly look for channels in use in 802.11b/g
- Decide what authentication mechanism you want to use (WPA-PSK,WPA2-PSK, 802.1x or Captive Portal)
Why use Aruba:
* encrypted all the way
* advanced buil-tin firewall
* easy to use web GUI
