Mac vs PC! What size laptop should I get?

So I need a new laptop. My current one is 4.5 years old and pretty broken and will prob die any day. My current one is a 15 inch Sony Vaio.
Here's its Specs:
i5-2410M processor (2.30GHz) with Turbo Boost up to 2.90GHz
6GB
Intel® Graphics Media Accelerator HD with Intel® Wireless Display technology
640GB (5400rpm) hard drive

I almost never had issues with my computer. My main problem has been battery life. However, I've seen my screen compared with some friends screens and I want better graphics for sure.

I bought my old computer when I thought I was gonna need to do a lot of video editing, but now I'm an English major, so I'm pretty sure some of those upgrades were a waste. I'm a student so I use my computer a lot and need to take it with me. I don't own a TV and I watch a ton of shows and youtube and netflix and stuff, so I definitely want something where I won't have issues there. I do some minor photoshop work, but nothing on a professional level.
Just looking for the best computer and something that will hopefully increase my experience and definitely not decrease it.

Currently, for financial reasons, I am torn between a 13inch Macbook (probably Pro, maybe Air) or a 15 inch PC (leaning towards Lenovo).

I just can't decide if I can go to that much of a smaller computer and if I can deal with that screen size.
However, I hear a lot of good things about Macs and its really appealing to get that computer.

Any words of wisdom/advice? Things to consider?

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