|MCP2515 and MCP2551|
The MCP2515 and MCP2551 seem to be the most common chips used by DYI/Arduino/etc users, not that surprising as there aren't that many breadboard friendly CAN chips available. For example the is a new controller available by Microchip, the MCP25625 with integrated CAN bus tranceiver, but it is not trough hole friendly as it is only available in SSOP-28L and 6x6 QFN-28L. But I wouldn't be surprised if someone will offer breakoutboards soon.
But one new chip is quite nice for users of 3.3V systems, for example the Arduino Due that has 2 CAN busses included in the Atmel SAM3X8E ARM Cortex-M3 CPU but no transceiver. The MCP2562 transceiver, it has separate voltages for the IO and CAN bus part, so you can plug it directly into any low-voltage device without the need of any level converters. I need to get myself some of those for my Due as I would prefer as little extra components as possible.