Android L was already launched in Google I/O developer conference but they had not officially mentioned when Devices to Get Android L Update. Here is the list which May get or may not get Android L update.
List of Devices to Get Android L Update soon
Google Devices: It would be Nexus 4, 5 and 7 will get Android L update. Android L developer preview already got few for Nexus 5 and 7 few month back and Nexus 4 will also get this update soon but not sure.
Motorola Devices: Moto X and Moto G will get sure update and also Moto X 2, Moto E and Moto G 2. These devices runs on Latest Android 4.4.4 right now. But its expected that Motorola Phones will be getting android L update soon after its release.
Samsung Devices : The phones that will be getting Android L updates like Samsung Galaxy S4, S5, S5 Active, Note 3 and Note 4. We can also see updates on Tab 4 , Pro and Tab S upcoming Phones. Lets see how samsung will work on new update and will provide Android L to all users.
HTC Devices : HTC One , M7 , M8 , and One Max will get updated to Android L. But there are very less chances that HTC Desire 816 and HTC Desire 516 can get this update.
LG Devices : LG G2 phone wont get Android L update But phones like G3, G Flex, Optimus Pro 2 and LG G Pad 8.3 . I hope LG G2 will also get new update.
Sony Devices : Sony Xperia Z1, Xperia Z1 Compact, Sony Xperia Z2, Xperia Z2 Tab, Xperia Z Ultra, Xperia M2 and Xperia T2 Ultra will be getting Android L updates .
But the question is when these devices will get Android L update ? May be in december 2014. But surely , Google and Motorola devices will get first update.
More info on Android L wiki