Well I'll give some honest feedback.
It looks good, but it doesnt look like a shareware game. Not quite. Needs tweaking!
The side menu is way too simple, you can even see the bevel of the photoshop / paintshop effect. The font just doesn't really fit well in the current design. You have a really simple side menu, but then quite an intricate detailed font. You need to add some variation. More then just a white beveled block that casts a shadow. How about a very tall candy cane, a reath in teh corner, a pile of presents or maybe just some more colored rectangles for the different sections. Just something that stands out more.
The whole menu casts a drop shadow, but your drop shadow gives away that the menu is a rectangle. See at the top you can see the top edge casting a shadow on the playfield. Well if this is what you want then ok. To me it looks a bit weird. You have a what is supposed to be floating menu, yet it fills the entire height of the screen, with 3 of its sides docked.
I would suggest either padding around the menu about 4 - 5 pixels or making the shadow continue right up to the top of the screen. The Padded menu could be interesting, you would have a small glimpse of the background, left,top and bottom of the menu. The casted shadow would also look alot cooler.
The play icons look excellent, apart from the bauball. It really shouldnt be faceated and really as somone else mentioned should be red. The colors you have chosen make it look like quite cold and bleak.
I am not trying to poke holes in this, but as you are trying to aim this at a buying market rather then a freeware market, I thought you might appreciate feedback of this nature.
The background really has no significance to christmas and the amount of blue you have there makes me shiver. To me for some reason it looks like the intro screen to a televised christian church service rather then a warm friendly holiday game.

Well there was my detailed critcisms's's's's of your shot. Hope you dont take offense!
ta ta