Time for an Upgrade? From the Rebel XTi to T3i/T5i? Or lenses/tripod?

Hello everyone! I've been a lurker on this site for some time now, but have been enthusiastic in joining up with you photographers! I've been involved in photography for almost a year now (along with post-processing via Adobe Lightroom) but have been itching to make an upgrade to my camera equipment, especially with Black Friday deals coming up and many others as well for the holidays.

My interest in photography ranges from portraiture to landscape/wildlife to street photography and studio (possibly travel). I am aware that when it comes to photography, it's not the gear that makes you a great photographer, but your skill, techniques, and creativity with it. I do aspire to be a professional photographer in many years to come (got my sights on Canon 6D for professional in the far future). I also do know that there is much I have yet to learn. However, at the moment, I am a novice looking to become an intermediate in the field of photography.

To start, I've only used the Rebel Xti since January, with the old kit lens (18-55mm f/3.5-5.6) and the recently bought Canon 50mm f/1.8 STM. While I've worked with the kit lens for quite a long while now, the 50mm lens has really served an improvement in exploring photography through discovering bokeh, seeing how useful a prime lens can be in comparison to a zoom lens, and exploring different skills and techniques with a prime lens. However, with no other equipment at my side, I am currently satisfied with how the XTi has performed so far. However, I am thinking that maybe it's time I expand my camera equipment. Only question is: what to buy?

I am unsure whether it is ideal to upgrade the body, but I have researched numerous cameras (not just from Canon but Nikon, Sony, Pentax, etc.) to see what would be ideal for entry-level/intermediate. So far, I have both the Canon Rebel T3i and T5i in my sights (though I am open to other brands). But it seems as though both are really similar and that in terms of cost, the T3i would be the one to get. I don't really have much of an interest in video, but the T3i doesn't seem to be in stock as compared to the T5i. As much as I'd like to consider getting the 6D for the image quality, it is out of my budget. Image quality is essentially what I highly value, but am uncertain whether upgrading the body really makes a difference.

As for other camera equipment, I literally have no other equipment but just my camera and lens. I have been considering a tripod for sharp images and future use in landscape photography. I'm not really keen on buying any cheap tripods but rather an investment in one (of good quality) that will serve me well for several years. I have set my sights on the Manfrotto 055XPRO3 or the 190XPRO3. Weight isn't really a concern for me, but there is the ballheads to consider. The Kirk BH-3 is what I've looked at so far, but am unsure of its performance and quality.

Then last, but not least, there are the lenses to consider. As stated before, I only have the kit lens and the 50mm f/1.8 STM lens in my arsenal, but am keen on expanding. I've heard that is more ideal to invest more into lenses and have found a few to be quite worth:

• Canon EF 85mm f/1.8 USM (or EF 35mm f/2 IS USM)
• Canon EF-S 17-55mm f/2.8 IS USM
• Canon EF-S 55-250mm f/4-5.6 IS II

As much as I highly value versatility with lenses, there's always compromises. However, I am curious to know what one (or two) lenses would be ideal to get for the kind of photography I'll be doing?

I apologize for this long post, given that this is my first post. However, I am really eager to go further into photography and would like to know your thoughts on how to best proceed with camera equipment (body, tripod, or lenses?). Any thoughts?