will i notice a speed increase from 2gb to 4gb on my alum macbook when doing basic things web browsing opening up apps etc. not video editing/photoshop
I asked this question on this forum and for what I use my MacBook for (basically same as you) there would not be a significant difference. So I'm holding off upgrading the ram until my MacBook is at least another year older.
I would wait. The price of RAM is always coming down, and 2 GB is plenty for the vast majority of applications and web browsing. This time next year you will probably be able to buy a 2x2GB kit for 50-75% of what it costs now.