^I own a Clip and found navigating to be pretty snappy, even without having a larger screen. The overall design and form factor (not to mention sound) outweigh the screen size. For what it's worth, the OLED screen can be adjusted in Settings and has remained bright, crisp and fresh-looking in just about every lighting condition I've been through.
The 8GB Clip+ (which is the one I believe you're actually referring to) is not that much more expensive than the 4GB Clip+, at least on Amazon.com, so I say go with the 8GB. I don't know how much music you plan to put on your player, but 4GB is plenty for me (I'm currently using a Sansa Fuze). You can find the current listing of the Clip+'s here at Amazon
. Just make sure you buy the ones sold and shipped by Amazon; anything in stock and over $25 includes free standard shipping.
2GB - 8GB microSD cards are really cheap these days, particularly if you buy them from Amazon.com or Buy.com. If you're going to buy a microSD card, make sure it's sold by and shipped from those two sites directly, not a 3rd party seller, just to be safe. Also, if you buy the card later by itself, go through Buy.com since they often ship free on some items under $25. Buy.com sorts and ships stuff fast, and I've gotten items in less than a week with the free shipping.