Some of this is personal preference and/or what you happen to have on hand.
I have converted 1130, 1200 and 1241 from autonomous to LWAPP mode. I have also implemented the 1142 native LWAPP AP’s as well. The AP’s seem to be happiest when you have DHCP available locally instead of having everything statically addressed. This has a benefit in that when you have an AP fail, it is just a matter of swapping out AP’s, letting the new AP come up on the controller and then configuring it. I would suggest that one of your dhcp configuration options is to have the dns servers on your local network listed and have a DNS A record pointing to the primary WLC controller. I like using the local site router as the dhcp source as I can then use the debug dhcp server events command followed by term mon so that I can see when the AP is getting an ip address which gives me an idea of how long before the controller will see the AP and begin talking to it.
I have upgraded the AP’s using the standalone upgrade utility that can be downloaded from Cisco. If you have WCS, you have the option of running the conversation from autonomous to LWAPP mode using that. One “feature” I have run into is that your autonomous AP’s must be running almost the latest version of IOS or WCS will error out in trying to upgrade the AP to LWAPP. Using the Upgrade Utility, I have upgraded as many as 6 AP’s at the same time without incident.
A couple of things to be careful of. The first is to click on the drop down arrow besides the number of AP’s that you will be upgrading as the same time. The Utility will complain if you type the number in and wont start the process. Also, be VERY sure that you have entered both the ip address of a DNS server that has the A record for your WLC and the domain name for your internal zone. If you dont do at least the first, the AP will get converted to LWAPP mode and then wont talk to the controller because it doesnt have the ip address of the DNS server to find out the ip address of the WLC that it can initially talk to. I had this happen to me one time and thought that I had bricked the AP. I was able to come up with the option 43 line for dhcp configuration to force feed the controller ip address it after a reboot of the newly converted AP, it did start talking to the controller.
If you plan on implementing Mode N on your wireless network, you will have to swap out every AP on your network with a Mode N capable unit because the controller will only talk to mode A or mode N devices but it can have both up at the same time. If you plan on using your existing 1200 series AP’s and want to use them on mode A, take a close look at the mode A add-on card. It will need to be a RM-21 or RM-22 or the code that the controller will push down to it wont talk to the A side of the AP.
If you have a good high ceiling area to mount the AP on, you will be pleased with the 1130/1140 offerings. If you wont be able to ceiling mount the AP’s, then go with the 1142 as it can site on the top of filing cabinet or similar perch and should yield acceptable coverage. If you have a location that has wall mounted (as opposed to a ceiling mount) or has layed the AP on top of a filing cabinet, expect to hear complaints from them as to how reliable that the wireless coverage isnt. If they would mount the AP’s properly, they would have better results.