Ken has given you some good choices and the reasons why he is suggesting them.
Having sailed on some Maine and Vermont lakes in the past, I wonder why you seem
so concerned about the ability to sell the board when your skills improve?
In the beginning, you will want a smaller sail, so you learn sail handling techniques and transitions easily and quickly.
Something in the 5.5-6.5 m2 size range perhaps?
But, since you are on fresh water, @ 175 lbs, you won't do much planing with a sail that size until the wind gets to a minimum of 15-16 knots.
And, as Ken suggests, the amount of time on the water is going to have a significant effect on how fast your skills improve to the point where you are planing.
Once you have the skills, you will most likely buy a larger rig (in the 7.5-8.5 m2 range
would seem good for your lake conditions) and then you can plane whenever there is around 12 knots of wind.
My experience on the the NE USA lakes suggests you will not see even that much wind
much of the time in the summer.
So, you are going to want to keep a longboard/Hybrid for the light wind days, and at some point get a short board without a centerboard for higher wind days.
Of the boards in the current Starboard product offerings, the Rio M is probably the board that will give you the widest range of use. It's pretty good in light winds with a smaller rig (I use mine with a 5.0 m2 Sailworks Retro Ripper trainer sail most of the time when I'm teaching) and it powers up and planes quite well in shortboard mode with the center board up.
You could, of course, get a GO (I do not think the GO 155 would be your best choice for a fresh water beginner) and simply deal with a narrower overall range of use.
As Ken suggests, slogging around on a big shortboard in < 8 knots of wind is not much fun, so even a larger GO 175 is not going to be real exciting in really light winds as you cannot "rail it" up on the center board to get good upwind angles. This is an advanced technique, yes, but one that anyone sailing in ultra light and fluky winds soon learns.
Getting an regular old style longboard might be good as it will give you many hours of cruising enjoyment, but they tend to be fairly narrow so the learning curve is not as easy as the modern wider, more stable, longboards/transition boards like the Rio M.
The Phantom 320/380 could be good as well, but they are not quite as good in shortboard mode when compared to the Rio M.
Take a real hard look at your windspeeds..... mostly < 10 knots...... mostly 8-12 knots....
occasionally more than 12 knots?
If your winds are mostly < 10 I suggest the Rio M as it works, even with smaller sails,
pretty well in very light winds where a short board (GO 175) would not be much fun at all.
And, if you get something that's good in light winds, but works well in shortboard mode, you can take advantage of the little gusty windy periods that often occur on your sort of lakes.
Cruise around in longboard mode until the gusts come, switch to shortboard mode while there is some wind, switch back to longboard mode to get yourself home when the winds subside.
And, you will probaby never really want to sell such a board for use in your conditions as it suits so many conditions.
When you are ready for a shortboard, then you can get one, but remember, they only work well when the winds are over 10 knots, even with huge => 9.5 rigs.
Hope this helps,