Considering a Gaming PC

It will cost quite a lot more, but a rig purchased here should have an effective gaming life of as many of 5 years without upgrading much of anything. With a few upgrades, it's not unheard of for a DS rig to play nice for 8 years or longer.

Mostly, the up-to-date parts sold here are so advanced for the gaming task, a "sick" rig doesn't require all the best or most expensive parts.

You must determine what you want in a gaming monitor before all else. The GPU is the heart of a gaming system, so getting just the right card for your monitor is the best way to go. The more modestly you start, the less expensive will be your first build. Extremely upgradeable, you may fairly easily upgrade many parts in a DS build in the future when you think you want to. You may never need more RAM, but storage may run short. It's easy to install more drives later, and reasonable to have it done for you. Video cards are getting much stronger with every new generation, and are also easy to upgrade.

Best advice for a new user IMHO is to start with a 24" or 27" 1080p IPS monitor that can refresh at 144 Hz. This is a really good idea to keep the video costs (both monitor and GPU) affordable while you discover what you like about PC gaming. I've been playing on one of these for 11 years now, and the quality is very good. Reaching higher at the outset to a high refresh 1440p monitor will increase costs for the video subsystem about double, but not deliver even close to twice the experience.

After the monitor you need to power, what you are able to spend is the most important consideration.