I have a Lowepro Rezo 30 (I took off the extra flap and pocket on the front to make it moar slimmer and ghetto) carrying case, Olympus FL-36R bounce flash, and Olympus 202315 Adjustable Wrist Strap for the LX5. No fancy software.
I'm not in love with that case though and would probably look around for something else. The Case Logic TBC-303 might be a better choice.
This flash works great but it makes the camera quite top heavy and is pretty large (and costs almost as much as the camera). I obviously don't carry it around all the time. I originally bought the Nissin Speedlite Di 466 FT which is much cheaper but it didn't work well with the camera at all so I sent it back. Of course, the LX5 has a built in flash so you don't really need an external flash. I got this since I was planning to take only the LX5 to Christmas with me one year and my parent's house is always really dark.
I like the wrist strap but wouldn't mind something that feels a little more rugged.
I have thought about getting the LVF1 viewfinder but it doesn't seem worth the price.