Nearly each batterie has its advantage:

Sanyo RC2400 They took over 2800 mAh on the first charge, but on the next only 2400. 2300 mAh are already reached by the Sanyo RC2000, so the future will show how these cells are doing. I have put together a 20 cell pack for my Logo 20, soldered inline and with cables, the gram scale showed 1245g.
For comparison : The RC2000 with solder tabs and cables have a weight of 1216g.

Sanyo RC2000 : good for all electric helis.

Sanyo 1700 SCRC : Beside the R2000 , I am using a selected pack in my Logo30 , 30g lighter than Rc2000 Packs, so flighttime is nearly equal.

Sanyo 1000 AA : I use them in my Easy. 7-8 min of motor runtime, good for Speed400- motors and really nice in weight/capacity

Sanyo / Panasonic 250 AAA : a 7 cell pack was in my Bleriot III and one in the Taube , nice batteries for models with Speed280 or Speed300 - motor.

Sanyo 110 : are used for ilumination in some of my models.

NiMh 550 AAA : They are now used in my Taube (7 cells) flighttime over 15 min!

Chargers

After some homemade chargers and some cheap equipment I took this one :

It´s a ROBBE PowerPeak Infinity, input-voltage 12V,charges and discharges 1 to 30 cells. No problems so far. An end-of-charge-beeper and a PC-interface is available too.
The Infinity , for instance , can charge 20 cells with 5A , 24 cells with 4A, and 30 cells with 3A. You see, with 30 cells, you will have to wait nearly an hour to get the RC2000 charged. That´s why I wanted something better:

The Schulze ISL6-636+.
It charges 20 cells with 8 A and 30 with 6A. Charging current is controlled automatically and the batteries don´t get even really warm !