> Or I can get it moving on the x but if the player walks into tiles from the side the character won't respond.

Well, I've noticed one fallacy in your logic that is most probably what's leading to this:

		for (int i = 0; i < tileList.Count; i++)
			{
				if (potentialNewPosition.Intersects(tileList[i].GetRectangle))
				{
					position = oldPosition;
					colliding = true;
				}
			}

If a collision is found, the player's movement is simply 'cancelled'. Here, if he collides with a block, he simply is sent back to where he came from. What we should do when dealing with tile collision is not cancel a movement, sending the object back to its starting position, but rather *correct* it.

What your algorithm should do is place your player's hitbox outside of the colliding tile, but no further from it. For example, considering that your player is basically a rectangle, if it was found to be inside a tile, you could make it so that `Player.Right = Tile.X` (if he was moving rightwards), or `Player.Bottom = Tile.Y` (for downward movement), or `Player.X = Tile.Right` (leftward), or `Player.Y = Tile.Bottom` (upward). This places him right alongside the tile, outside.