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article on the radio choices, servo choices, batteries etc by J fisher

I will do a quick version now that I have access to a keyboard. j fisher

Any of the new 2.4 ghz radios seem to work fine.  The advantage is they all select an open channel before turning on or hop between channels while on to avoid interference. This includes the $30 hobby king radio.  The question you need to ask yourself is do I want a computer radio or can I live with a radio without the ability to mix servos or adjust end points on servo travel.  A computer radio will do both, a simple radio like HK will not.  There are very few if any 2 channel stick radios left in production, buy a 4 to 8 channel and only use 2.  You want Mode 2 radios as this puts the ratched on the left stick.  Personally I have a high end 7 channel that I use for all my boats.  I have one TX and it has a setup for each boat stored in the radio.  It works well, but doesnt allow you to have multiple boats sailing at once.  You could buy 10 Hobby King radios for what I paid for my TX.  There are radios between the two price points, you need to ask yourself what features you need.

There are lots of options, if you want cheap, hitech makes a nice drum winch along with some arm winches.  They run about $50 and offer plenty of torque.  The down side is they are slow.  There are also a bunch of $20 to $30 cheap chinese winches.  I have not tried any but I have read that the performance is mixed.  Some work well, some do not.  One case found that removing the o-ring on the output shaft solved the life issue.
The mid price but good performance option is digital 1/4 scale servo's.  They run $150 to $200 and offer extremely fast speeds with 300+ ozin of torque.  Most if not all are digital and can be programmed for up to 180 deg of travel.  they are the lightest available.  I have not used one, but they are commonly used on IOM's.  I would make sure that you use pulleys on your sheets as constant drag on the sheets can cause excessive heat for the servo. 
The last option is the RMG winch, I feel they are pretty much the standard which all the others are judged.  They will rip the boat apart if something jams, good battery life, good speed and decent weight.  Very programmable which eliminates the need for a programmable TX.  Due to being mfg in Australia,  the exchange rate effects price.  I bought several last time we had a favorable rate, that made them about $80 cheaper than today.
Rudder servo can be any standard servo.  Nothing special is needed.

Lipo or lithium polymer, very light, high discharge rates, fast charge and low self discharge.  Down side is they need a Lipo charger and can burst into flames if over or under charged, they are also 8.4 volts when fully charged.  This means you need a regulator for most radios.  Cost is now low from places like HK, a 1000 mah pack is less than $10.  I have used these since 2006 with no issues, you just have to take more care to make sure you dont discharge them below 3.3 volts per cell.  The RMG winch has a built in regulator and low voltage cut off, which removes two of the big issues with Lipo's.
LiFe or lithium iron batteries are similar to Lipo but have slightly lower voltage, a bit higher weight.  The advantage is they are more stable and will not burst into flames if abused.  Down sides are similar to Lipo and you need a LiFe charger which may be different than the Lipo versions.  These batteries are newer than the Lipo's.
Nimh or Nickel metal hydride a standard for years.  Still available.  They offer good battery life and reasonable weights.  They are also robust in that they can be discharged to low voltages with no damage.  The down sides are weight (heavier than Lipo Life), fast self discharge (have to charge before use), lower charge rates (may take several hours to charge if you want good charge retention).  I no longer use Nimh due to the slow charge rates required.  This is only an issue if you are doing multiple day regatta's.  A good choice for anyone who is hard on batteries.
Nicad or Nickel cadmium the old standard of rechargeable batteries.  Up side, cheap and durable.  Down side, heavy, low capacity, slow charge rates and low charge rates.  No reason to use them anymore as Nimh batteries have more capacity and are similar in other aspects.